Display Control Apparatus, Display Method, and Computer Program

ABSTRACT

A display control apparatus includes a search unit for searching for a second content linked to a first content and a display control unit for controlling display of a search history of content search performed in accordance with one of a first image and a first character, each indicating the first content, one of a second image and a second character, each indicating the second content and link information linking the first content to the second content.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese PatentApplication JP 2007-032583 filed in the Japanese Patent Office on Feb.13, 2007, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display control apparatus, a displaymethod and a computer program and, in particular, to a display controlapparatus, a display method and a computer program for displayinginformation relating to contents.

2. Description of the Related Art

Apparatuses are currently in widespread use to download a large numberof contents including still images, moving images and music via acommunication network and store such contents.

When a content is downloaded, the downloading of a content related tothe selected content is sometimes recommended. Some apparatuses displayinformation relating to a content of interest when the content ofinterest is selected to be played from among a large number of storedcontents.

Japanese Unexamined Patent Application Publication No. 8-263255discloses a display technique. In accordance with the disclosure, adisplay screen is partitioned into a plurality of areas with one areadisplaying data icons representing data belonging to a parent layer andanother area displaying a daughter layer. The younger (lower) the layer,the more each data icon in that layer is reduced in size. Further, thedata icon is displayed in the simpler form with the layer becominglower. The daughter layer is displayed within the background showing theparent layer. The younger the layer, the deeper the background colorbecomes. By performing a predetermined operation with a display area ofa desired layer pointed, the desired layer can be zoomed up, and azoom-out operation is thus smoothly performed from the zoomed layer tothe parent layer in response to a predetermined operation.

Japanese Unexamined Patent Application Publication No. 10-312392discloses another display technique. In accordance with the disclosure,two objects are displayed in an overlay fashion with one object cuttingaway the corresponding portion thereof from another object if the oneobject is contained in the other object. A layout direction of thecontained object to the containing object is fixed. If the number ofobjects contained in a planar object exceeds a predetermined number, thecontained objects corresponding to a leaf are arranged with respect tothe contained object corresponding to a node in two lines in a directionopposite from a direction of expansion.

Japanese Unexamined Patent Application Publication No. 2006-4292discloses yet another display technique. in accordance with thedisclosure, a function icon row composed a plurality of function iconsrepresenting types of media to be played and a function icon rowcomposed a plurality of content icons showing items of contents to beplayed are displayed to be intersected at an approximate center of amenu screen. A moving icon as a function icon displayed in anintersection area where the function icon row and the content icon rowintersect each other is displayed in enlargement and in a colordifferent from the other function icons. The layer structure of thecontents is visibly represented in the content icon row.

SUMMARY OF THE INVENTION

A content may be selected by tracking back a large number contentsthrough link. The link of the contents heretofore tracked cannot bedisplayed on a screen for selecting the content thereon.

It is thus desirable to allow the user to recognize the relationship ofthe tracked contents at a glance when the contents are tracked in asearching operation.

In accordance with one embodiment of the present invention, a displaycontrol apparatus includes a search unit for searching for a secondcontent linked to a first content, and a display control unit forcontrolling display of a search history of content search performed inaccordance with one of a first image and a first character, eachindicating the first content, one of a second image and a secondcharacter, each indicating the second content and link informationlinking the first content to the second content.

The display control unit may control the display of the search historyof the content search performed in accordance with the first image andthe second image, each being a thumbnail image, and the link informationbetween the first content and the second content.

The display control unit may control the display of the search historyincluding an image indicating a link between one of the first image andthe first character and one of the second image and the secondcharacter.

The search unit may search for the second content having the samemetadata as metadata of the first content.

The search unit may search for a third content linked to the secondcontent, and the display control unit may control the display of thesearch history of the content search performed in accordance with one ofthe first image and the first character, one of the second image and thesecond character, one of a third image and a third character, eachindicating the third content, the link information linking the firstcontent to the second content and link information linking the secondcontent to the third content.

The display control apparatus may further include a generating unit forgenerating a three-dimensional model, the three-dimensional modelincluding a first layer having one of the first image and the firstcharacter of the first content arranged therewithin, a second layerhaving one of the second image and the second character of the secondcontent arranged therewithin and a third layer having one of the firstimage and the first character, one of the second image and the secondcharacter and text indicating the link information between the firstcontent and the second content. Using the three-dimensional model, thedisplay control unit may control the display of the search history ofthe content search performed in accordance with one of the first imageand the first character, one of the second image and the secondcharacter and the text indicating the link information between the firstcontent and the second content.

The display control unit may control the display of the search historyof the content search performed in accordance with the link informationindicating both a category related to each of the first content and thesecond content and a specific content of the category.

The search unit may search for the second content linked to the firstcontent in accordance with at least part of metadata attached to each ofthe first content and the second content.

The display control unit may control the display of the search historyin a two-dimensional image and control the display of the content searchin a three-dimensional image if the second content is searched.

In accordance with one embodiment of the present invention, a displaymethod include steps of searching for a second content linked to a firstcontent, and displaying a search history of content search performed inaccordance with one of a first image and a first character, eachindicating the first content, one of a second image and a secondcharacter, each indicating the second content and link informationlinking the first content to the second content.

In accordance with one embodiment of the present invention, a computerprogram for causing a computer to perform a display control method,includes steps of searching for a second content linked to a firstcontent, and controlling display of a search history of content searchperformed in accordance with one of a first image and a first character,each indicating the first content, one of a second image and a secondcharacter, each indicating the second content and link informationlinking the first content to the second content.

In accordance with embodiments of the present invention, the secondcontent linked to the first content is searched for and display of asearch history of content search is controlled. The content search isperformed in accordance with one of the first image and the firstcharacter, each indicating the first content, one of the second imageand the second character, each indicating the second content and thelink information linking the first content to the second content.

In accordance with embodiments of the present invention, informationrelating to contents is displayed.

In accordance with embodiments of the present invention, if linking ofcontents is tracked in searching, a relationship of the tracked contentscan be viewed at a glance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a hardware structure of apersonal computer as one example of a display control apparatus inaccordance with one embodiment of the present invention;

FIG. 2 is a functional block diagram illustrating the personal computerexecuting a program;

FIG. 3 illustrates the structure of a model parameter determiner;

FIG. 4 illustrates display modes of the personal computer;

FIG. 5 illustrates a display example displayed on a display in an outputunit;

FIG. 6 illustrates a display example displayed on the display in theoutput unit;

FIG. 7 illustrates a display example displayed on the display in theoutput unit;

FIG. 8 illustrates a display example displayed on the display in theoutput unit;

FIG. 9 illustrates a display example displayed on the display in theoutput unit;

FIG. 10 illustrates a display example displayed on the display in theoutput unit;

FIG. 11 illustrates a display example displayed on the display in theoutput unit;

FIG. 12 illustrates a display example displayed on the display in theoutput unit;

FIG. 13 illustrates a display example displayed on the display in theoutput unit;

FIG. 14 illustrates a display example displayed on the display in theoutput unit;

FIG. 15 illustrates a display example displayed on the display in theoutput unit;

FIG. 16 illustrates a display example displayed on the display in theoutput unit;

FIG. 17 illustrates a display example displayed on the display in theoutput unit;

FIG. 18 illustrates a display example displayed on the display in theoutput unit;

FIG. 19 illustrates a display example displayed on the display in theoutput unit;

FIG. 20 illustrates a display example displayed on the display in theoutput unit;

FIG. 21 illustrates a display example displayed on the display in theoutput unit;

FIG. 22 illustrates a display example displayed on the display in theoutput unit;

FIG. 23 illustrates a display example displayed on the display in theoutput unit;

FIG. 24 illustrates a display mode of the personal computer;

FIG. 25 is a flowchart illustrating a display process in a top-pagemode;

FIG. 26 is a flowchart illustrating a display process in a relatedsearch mode;

FIG. 27 is a flowchart illustrating a determination process of aparameter of a model;

FIG. 28 is a flowchart illustrating a focused display process of a modelof related content;

FIG. 29 is a flowchart illustrating a layer addition process;

FIG. 30 is a continuation of the flowchart of FIG. 29;

FIG. 31 is a flowchart illustrating a line addition process;

FIG. 32 is a flowchart illustrating a return process to return to theimmediately preceding line;

FIG. 33 is a flowchart illustrating a display process in a summary mode;

FIG. 34 illustrates a display example displayed on the display in theoutput unit;

FIG. 35 illustrates a display example displayed on the display in theoutput unit;

FIG. 36 illustrates a display example displayed on the display in theoutput unit;

FIG. 37 illustrates a display example displayed on the display in theoutput unit;

FIG. 38 illustrates a display example displayed on the display in theoutput unit;

FIG. 39 illustrates a display example displayed on the display in theoutput unit;

FIG. 40 illustrates a display example displayed on the display in theoutput unit;

FIG. 41 illustrates a display example displayed on the display in theoutput unit;

FIG. 42 illustrates a display example displayed on the display in theoutput unit;

FIG. 43 illustrates a display example displayed on the display in theoutput unit;

FIG. 44 illustrates a display example displayed on the display in theoutput unit;

FIG. 45 illustrates a display example displayed on the display in theoutput unit;

FIG. 46 illustrates a display example displayed on the display in theoutput unit;

FIG. 47 illustrates a display example displayed on the display in theoutput unit;

FIG. 48 illustrates a display example displayed on the display in theoutput unit;

FIG. 49 illustrates a display example displayed on the display in theoutput unit;

FIG. 50 illustrates a display example displayed on the display in theoutput unit;

FIG. 51 is a functional block diagram illustrating another personalcomputer executing a program;

FIGS. 52A-52D illustrates display examples displayed on a display in anoutput unit;

FIG. 53 is a flowchart illustrating a process for searching a relatedcontent and specifying a display method;

FIG. 54 is a functional block diagram illustrating another personalcomputer executing a program;

FIG. 55 illustrates an example of metadata;

FIG. 56 illustrates an example of similarity;

FIG. 57 is a flowchart illustrating a process for searching a relatedcontent and specifying a display method;

FIG. 58 is a functional block diagram illustrating yet another personalcomputer executing a program;

FIG. 59 illustrates a preference vector that represents the preferenceinformation;

FIG. 60 illustrates an example of similarity;

FIG. 61 is a flowchart illustrating a process for searching a relatedcontent and specifying a display method;

FIG. 62 is a functional block diagram illustrating still anotherpersonal computer executing a program;

FIG. 63 illustrates an example of an evaluation value;

FIG. 64 illustrates a display example displayed on a display in anoutput unit;

FIG. 65 is a flowchart illustrating a process for searching a relatedcontent and specifying a display method;

FIG. 66 is a functional block diagram illustrating a personal computerexecuting a program;

FIG. 67 illustrates an example of metadata;

FIG. 68 illustrates an example of metadata;

FIG. 69 illustrates an example of metadata;

FIG. 70 illustrates display examples displayed on a display in an outputunit;

FIG. 71 illustrates display examples displayed on the display in theoutput unit;

FIG. 72 is a flowchart illustrating a process for searching a relatedcontent and specifying a display method;

FIG. 73 is a functional block diagram illustrating a personal computerexecuting a program;

FIG. 74 illustrates an example of metadata;

FIG. 75 illustrates an example of cosine distance;

FIG. 76 illustrates display examples displayed on a display in an outputunit;

FIG. 77 illustrates display examples displayed on the display in theoutput unit;

FIG. 78 is a flowchart illustrating a process for searching a relatedcontent and specifying a display method;

FIG. 79 is a functional block diagram illustrating a personal computerexecuting a program;

FIG. 80 illustrates metadata linking selected starting contents;

FIG. 81 illustrates an example of search history;

FIG. 82 illustrates an example of metadata;

FIG. 83 illustrates linked contents;

FIG. 84 illustrates a display example displayed on a display in anoutput unit;

FIG. 85 is a flowchart illustrating a search process of the relatedcontent;

FIG. 86 is a flowchart illustrating a display process of the relatedcontent;

FIG. 87 is a functional block diagram illustrating a personal computerexecuting a program;

FIG. 88 illustrates preference information as a vector;

FIG. 89 is a flowchart illustrating a storage process of the preferenceinformation;

FIG. 90 is a functional block diagram illustrating a personal computerexecuting a program;

FIG. 91 illustrates an example of metadata;

FIG. 92 illustrates a display example displayed on a display in anoutput unit;

FIG. 93 illustrates a display example displayed on the display in theoutput unit; and

FIG. 94 is a flowchart illustrating a narrowing process of the relatedcontents.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before describing an embodiment of the present invention, thecorrespondence between the elements of the inventions and the specificelements disclosed in an embodiment of the present invention isdiscussed below. This description is intended to assure that embodimentssupporting the invention are described in this specification. Thus, evenif an element in the following embodiments is not described as relatingto a certain element of the present invention, that does not necessarilymean that the element does not relate to that element of the presentinvention. Conversely, even if an element is described herein asrelating to a certain element of the present invention, that does notnecessarily mean that the element does not relate to other elements ofthe present invention.

In accordance with one embodiment of the present invention, a displaycontrol apparatus includes a search unit (for example, related contentsearcher 57 of FIG. 2) for searching for a second content linked to afirst content, and a display control unit (for example, displaycontroller 55 of FIG. 2) for controlling display of a search history ofcontent search performed in accordance with one of a first image and afirst character, each indicating the first content, one of a secondimage and a second character, each indicating the second content andlink information linking the first content to the second content.

The display control apparatus may further include a generating unit (forexample, three-dimensional model generator 54 of FIG. 2) for generatinga three-dimensional model, the three-dimensional model including a firstlayer having one of the first image and the first character of the firstcontent arranged therewithin, a second layer having one of the secondimage and the second character of the second content arrangedtherewithin and a third layer having one of the first image and thefirst character, one of the second image and the second character andtext indicating the link information between the first content and thesecond content. Using the three-dimensional model, the display controlunit may control the display of the search history of the content searchperformed in accordance with one of the first image and the firstcharacter, one of the second image and the second character and the textindicating the link information between the first content and the secondcontent.

In accordance with one embodiment of the present invention, one of adisplay method and a computer program include steps of searching for asecond content linked to a first content (for example, in step S110 ofFIG. 29), and displaying a search history of content search performed inaccordance with one of a first image and a first character, eachindicating the first content, one of a second image and a secondcharacter, each indicating the second content and link informationlinking the first content to the second content (for example, in stepS190 of FIG. 33).

FIG. 1 is a block diagram illustrating the hardware structure of apersonal computer as one example of a display control apparatus inaccordance with one embodiment of the present invention. In the personalcomputer, a central processing unit (CPU) 11, a read-only memory (ROM)12 and a random-access memory (RAM) 13 are interconnected to each othervia a bus 14.

The bus 14 connects to an input-output interface 15. Connected to theinput-output interface 15 are an input unit 16 including a keyboard, amouse, a microphone and a touchpanel, an output unit 17 displaying animage and/or emitting a sound, a hard disk drive 18 including arecording medium, a communication unit 19 including a network interfaceand a drive 20 for driving a removable medium 21 such as a magneticdisk, an optical disk, a magneto-optical disk or a semiconductor memory.

The output unit 17 includes a display 31 such as a liquid-crystaldisplay (LCD), and a loudspeaker 32.

In the computer thus constructed, the CPU 11 loads a program stored onthe hard disk drive 18 to the RAM 13. The CPU 11 executes the programloaded on the RAM 13, thereby performing a series of process steps to bedescribed later.

The program to be executed by the CPU 11 as one example of computer isrecorded on the removable medium 21 as a package medium including one ofa magnetic disk (such as a flexible disk), an optical disk (such ascompact disk read-only memory (CD-ROM) or digital versatile disk (DVD)),a magneto-optical disk and a semiconductor memory and then supplied. Theprogram may also be supplied via a wired or wireless communicationmedium such as a local area network, the Internet or a digitalbroadcasting satellite.

By loading the removable medium 21 on the drive 20, the program isstored onto the hard disk drive 18 via the input-output interface 15.The program is thus installed on the personal computer. The program canalso be received by the communication unit 19 via the wired or wirelesscommunication medium and then stored on the hard disk drive 18 forinstallation. The program can also be pre-stored on one of the ROM 12and the hard disk drive 18 for pre-installation.

FIG. 2 is a functional block diagram illustrating a personal computerexecuting the program. The functional blocks illustrated in FIG. 2 areimplemented when the personal computer executes the program. Thepersonal computer includes an input controller 51 controlling the inputunit 16, a mode determiner 52, a model parameter determiner 53, athree-dimensional model generator 54, a display controller 55controlling the display 31, a genre-sorted content selector 56, arelated content searcher 57, a history storage 58, a player 59, acommunication controller 60 controlling the communication unit 19, ametadata database 61, a bookmark database 62 and a content database 63.

The input controller 51 is implemented by executing a driver of theinput unit 16 as a program. The input controller 51 supplies data toeach element of the personal computer in response to an operation of auser applied to the input unit 16 including the keyboard and thetouchpanel.

The mode determiner 52 determines one of personal computer modesincluding a top-page display mode, a related search mode, a play mode, asummary mode and a overhead-view mode. The modes will be described indetail later.

The model parameter determiner 53 determines a parameter to identify athree-dimensional model. The three-dimensional model displaysinformation, relating to contents, such as a thumbnail image andmetadata of each content.

The thumbnail image is one example of image representing a content andmay be produced from an image contained in the content or from a recordjacket photograph.

The image forming a three-dimensional model may be anything representingthe content and is not limited to the thumbnail image.

The thumbnail image is hereinafter quoted as an image representing thecontent.

The contents are data useful for a user and include a still image, amoving image, music (song), books (image and text), etc.

The parameters include information identifying a content, a thumbnailimage as a still image, a scale-contracted moving image, informationidentifying the type of a model such as text, information identifying athumbnail image used as a model and the number of models such asthumbnail images arranged along a line to be discussed later. The modelparameter determiner 53 supplies the determined parameter to thethree-dimensional model generator 54.

The three-dimensional model with the parameter thereof determined by themodel parameter determiner 53 includes a model of at least one content.

The model of the content refers to a thumbnail image of the content, ascale-contracted moving image of a moving image content, text indicatinginformation related to the content (for example, metadata such as adescription attached to the content), text indicating informationrelated to at least one content (for example, category to be discussedlater), and a model indicating a group of a plurality of models.

Based on the parameter supplied by the model parameter determiner 53,the three-dimensional model generator 54 generates the three-dimensionalmodel displaying a thumbnail image or metadata of a content. Forexample, the three-dimensional model is described using virtual realitymodeling language (VRML). The three-dimensional model generator 54supplies the generated three-dimensional model to the display controller55. The three-dimensional model generator 54 generates athree-dimensional display model in which one of an image such as athumbnail image representing a predetermined content and a characterrepresenting the content is arranged in a predetermined layer and one ofan image, such as a thumbnail image, of another content related to thepredetermined content and a character representing the other content isarranged in another layer. The three-dimensional model generator 54 willbe described more in detail later.

The display controller 55 is implemented by executing a driver of thedisplay 31 as a program. The display controller 55 causes the display 31as an LCD to display one of the thumbnail image and the metadata of thecontent. For example, the display controller 55 causes the display 31 todisplay one of the thumbnail image and the metadata of the content bydrawing and displaying the three-dimensional model.

Using a display model generated by the three-dimensional model generator54, the display controller 55 controls displaying one of the image andthe character of the predetermined content and one of the image and thecharacter of the other content related to the predetermined content.

When a search history of contents is displayed, the display controller55 controls displaying the predetermined image representing thepredetermined content, the other image representing the other contentrelated to the predetermined content and the search history of thecontents based on a link between the predetermined content and the othercontent.

In response to a user operation on the input unit 16, the genre-sortedcontent selector 56 selects a content belonging to a genre selected bythe user in the top-page mode.

In the related search mode, the related content searcher 57 searches forcontents related to the content selected by the user in response to theuser operation on the input unit 16. For example, the related contentsearcher 57 searches for a content related to the predetermined contentin accordance with at least part of the metadata attached to thecontents.

A content searched, hit and related to the content selected by the useris referred to as a related content. When the related contents aresearched, the original content selected by the user is referred to as astarting content.

The history storage 58 stores the search history of the relatedcontents.

In the play mode, the player 59 plays the content selected by the userin response to the user operation applied to the input unit 16. Forexample, the player 59 reads the content from the content database 63and plays the content. The player 59 can also play a content received bythe communication unit 19.

The communication controller 60 is implemented by executing the programof the driver of the communication unit 19 serving as a networkinterface. The communication controller 60 transmits and receives avariety of data via a network.

The communication controller 60 causes the communication unit 19 as thenetwork interface to receive the content to be played from a server (notshown) via the network. The communication controller 60 causes thecommunication unit 19 to receive data related to the content, such asmetadata of the content, from the server (not shown) via the network.

Each of the metadata database 61, the bookmark database 62 and thecontent database 63 has a database management function implemented byexecuting a database management program and includes a recording areahaving a predetermined recording capacity of a recording area of thehard disk drive 18 and managed by the database management function.

The metadata database 61 stores the metadata attached to the content.For example, the metadata database 61 stores the metadata attached tothe content stored on the content database 63. In other words, themetadata database 61 stores the metadata mapped to the content stored onthe content database 63. When requested to read any content or metadataas a key, the metadata database 61 supplies the metadata mapped to thekey.

The bookmark database 62 stores information identifying a bookmarkedcontent as a content selected by the user.

The content database 63 stores the content. When requested to read anycontent or metadata as a key, the content database 63 supplies thecontent mapped to the key.

The mode determiner 52 includes a viewpoint specifier 71. The viewpointspecifier 71 specifies a viewpoint at the drawing of thethree-dimensional model to the display controller 55.

The three-dimensional model generator 54 stores model template data 72.The model template data 72 is template data such as a color of a groupof at least one model, a thickness of a line connecting thumbnail imagesand a pattern of the line, such as a solid line or a broken line, withsuch color or line serving to surround at least one model such as thethumbnail image of the content searched and hit according to apredetermined category to be described later.

The display controller 55 includes a drawing unit 73. The drawing unit73 draws the three-dimensional model supplied from the three-dimensionalmodel generator 54, thereby generating display data to be displayed onthe display 31.

The related content searcher 57 includes a category selector 74. Thecategory selector 74 selects a category of the related content to besearched. As will be described more in detail later, the category isrelated to both the related content and the starting content.

The history storage 58 includes a related content search history storageunit 75 and a starting content selection history storage unit 76. Therelated content search history storage unit 75 stores the search historyof the related content. The starting content selection history storageunit 76 stores the selection history of the starting content.

FIG. 3 illustrates the structure of the model parameter determiner 53.The model parameter determiner 53 includes a focus position determiner101, a layer layout determiner 102, a transparency determiner 103, atop-page model parameter determiner 104, a related search modelparameter determiner 105, a summary model parameter determiner 106 and amodel parameter storage 107.

The focus position determiner 101 determines a parameter indicating afocus position, from among parameters identifying the three-dimensionalmodel.

The layer layout determiner 102 determines a parameter describing aposition in the metadata of the layer where a model such as a thumbnailimage is arranged.

The transparency determiner 103 determines a parameter describing thedegree of transparency of a model.

The top-page model parameter determiner 104 determines a parameter ofthe three-dimensional model for displaying a top page in the top-pagemode. The parameter identifies a model such as a thumbnail image or textdisplayed on the top page.

The related search model parameter determiner 105 determines a parameterof the three-dimensional model for displaying a model such as athumbnail image of the related content and a thumbnail image of thestarting content in the related search mode. More specifically, therelated search model parameter determiner 105 determines the model as aparameter identifying the thumbnail image of the related content and aparameter describing the layout of the model as the thumbnail image.

The summary model parameter determiner 106 determines a parameter of thethree-dimensional model for displaying a model such as a thumbnail imageof the starting content in the summary mode. More specifically, thesummary model parameter determiner 106 determines a parameteridentifying the model as the thumbnail image of the starting content anda parameter describing the layout of the model as the thumbnail image.

The model parameter storage 107 stores the parameters of thethree-dimensional model to be displayed.

The related search model parameter determiner 105 further includes astarting model layout determining unit 121, a related model structureand layout determining unit 122, a detailed information model layoutdetermining unit 123 and a moving image model layout determining unit124.

The starting model layout determining unit 121 determines a parameteridentifying the layout of a model such as a thumbnail image of thestarting content.

The related model structure and layout determining unit 122 determines aparameter describing the number models such as thumbnail images of therelated content, a parameter identifying the thumbnail image of therelated content used as a model and a parameter identifying the layoutof each of model as the thumbnail image.

The detailed information model layout determining unit 123 determines aparameter identifying detailed information of the related content usedas a detailed information model and a parameter identifying the layoutof the detailed information model.

The moving image model layout determining unit 124 determines aparameter identifying the layout of a model as a scale-contracted movingimage of one of the related content and the starting content as a movingimage.

The display on the display of the display 31 in the output unit 17 isdescribed below.

As shown in FIG. 4, the display modes of the personal computer includefive modes, namely, the top-page mode, the related search mode, the playmode, the summary mode and the overhead-view mode. The top-page mode isused to display a list of contents on a per genre on the screen andappears first when a display process starts. The related search mode isused to search for a content related to a content selected by the userin response to a user operation applied on the input unit 16. In therelated search mode, contents linked to the content selected by the userare searched.

The related content is a content related to a predetermined content,namely, a content linked to the predetermined content. The startingcontent is an original content linked to the related content.

The play mode is used to play the content.

The summary mode is used to display a list of starting contents in thesearch process of the related search mode. More specifically, in thesummary mode, the thumbnail image of the related content linked to thestarting content searched in the related search mode and the thumbnailimage of the starting content are displayed and information linked tothe starting content and the related content is also displayed.

The overhead-view mode is used to view the process of related searchwith a viewpoint of a camera changed. The viewpoint of the camera servesas a reference in the drawing of the three-dimensional model view.

The top-page mode as one display mode of the personal computer istransitioned to one of the related search mode, the play mode and thesummary mode. The related search mode as one display mode of thepersonal computer is transitioned to one of the play mode, the summarymode and the overhead-view mode in response to a user operation.

The play mode as one display mode of the personal computer istransitioned to one of the top-page mode and the related search mode inresponse to a user operation. The summary mode as one display mode ofthe personal computer is transitioned to one of the top-page mode andthe related search mode in response to a user operation.

The overhead-view mode as one display mode of the personal computer istransitioned to the related search mode in response to a user operation.

Display examples displayed on the display 31 in the output unit 17 ineach of the top-page mode, the related search mode, the play mode, thesummary mode and the overhead-view mode are described below withreference to FIGS. 5 through 23.

In the discussion that follows, the models of the contents include athumbnail image of a content, a scale-contracted moving image of amoving image content, and detailed information of a content expressed intext.

FIGS. 5 through 9 illustrate the transition from the top-page mode orthe screen in the top-page mode to another display mode.

When the display process starts, the screen of the top-page mode isdisplayed on the display 31 in the output unit 17 as shown in the topportion of FIG. 5. Arranged on one row in the top-page mode screen arebuttons for selecting genre for my page, action, animation, sciencefiction (SF), horror, comedy, etc. One of the buttons for selectinggenre is focused or selected.

Thumbnail images of contents belonging to the genre of the buttonfocused or selected are arranged in a horizontal line on the bottomportion of the top-page mode screen.

When the display process starts, one button is selected as a defaultbutton from among the genre selecting buttons. For example, the buttonfor action genre is selected as shown in FIG. 5.

When the display process starts, a leftmost thumbnail image from amongthumbnail images of the contents belonging to the genre of the buttonselected as default is focused as default. For example, the leftmostthumbnail image on the screen is focused from among the thumbnail imagesbelonging to the action genre as shown in FIG. 5.

When the display process starts, the focusing of the button for genreselection becomes invalid, and the focusing of the thumbnail imagebecomes valid.

If an upward looking arrow key of the keyboard in the input unit 16 ispressed with the thumbnail image focused, the button for the selectedgenre is focused. In other words, focusing shifts to the button of theselected genre.

If the upward looking arrow key of the keyboard in the input unit 16 ispressed with the thumbnail image focused, focusing of the button forselecting genre becomes valid while focusing of the thumbnail imagebecomes invalid.

If a rightward looking arrow key of the keyboard in the input unit 16 ispressed with the button for selecting genre focused as shown in FIG. 6,a button arranged to the right of the heretofore focused button isfocused on the top-page mode screen. More specifically, focusing shiftsrightward across the genre selecting buttons.

Thumbnail images of the contents belonging to the genre of the focusedbutton are arranged in a horizontal line on the bottom side of thetop-page mode screen.

For example, if the rightward looking arrow key of the keyboard in theinput unit 16 is pressed four times consecutively with the action genrebutton focused, the comedy genre button is focused. The comedy genrebutton is on the right side of the action genre button and spaced fromthe action genre button by three buttons. Thumbnail images of contentsbelonging to the comedy genre are arranged in a horizontal line on thebottom portion of the top-page mode screen.

If a leftward looking arrow key of the keyboard in the input unit 16 ispressed with the button for selecting genre focused, a button to theleft of the heretofore focused button is focused on the top-page modescreen. More specifically, focusing shifts leftward across the genreselecting buttons.

If a downward looking arrow key of the keyboard in the input unit 16 ispressed with a genre selecting button focused, the genre correspondingto the focused button is selected. Focusing shifts to one of thethumbnail images of the contents arranged in a horizontal line on thebottom portion of the top-page mode screen.

In other words, if the downward looking arrow key of the keyboard in theinput unit 16 is pressed with the genre selecting button focused,focusing of the genre selecting button becomes invalid while focusing ofthe thumbnail image becomes valid.

For example, if the downward looking arrow key of the keyboard in theinput unit 16 is pressed with the comedy genre button focused, theleftmost thumbnail image from among the thumbnail images of the contentsbelonging to the comedy genre is focused on the screen.

As shown in FIG. 7, if the rightward looking arrow key of the keyboardin the input unit 16 is pressed with the thumbnail image focused, athumbnail image to the right of the thumbnail image heretofore focusedon the top-page mode screen is focused. More specifically, focusingshifts rightward across the thumbnail images.

For example, if the rightward looking arrow key of the keyboard in theinput unit 16 is pressed three times consecutively with the leftmostthumbnail image focused on the screen, the fourth thumbnail image fromthe leftmost thumbnail image is focused.

If the leftward looking arrow key of the keyboard in the input unit 16is pressed with a thumbnail image focused, a thumbnail image to the leftof the heretofore focused thumbnail image is focused on thethree-dimensional model. More specifically, focusing shifts leftwardacross the thumbnail images.

If an enter key of the keyboard in the input unit 16 is pressed with thethumbnail image focused as shown in FIG. 8, the thumbnail image isselected. The content of the thumbnail image is then selected, thepersonal computer shifts to the play mode and the selected contentstarts to be played.

If the content is a moving image in the play mode as shown in the bottomportion of FIG. 8, the moving image is expanded and displayed instead ofthe focused thumbnail image.

If a left square bracket key (“[” symbol key) of the keyboard in theinput unit 16 is pressed with the thumbnail image focused as shown inFIG. 9, the content of the focused thumbnail image is selected as astarting content. The personal computer is transitioned to the relatedsearch mode.

In the related search mode, a layer for displaying the thumbnail imageof the related content related to the starting content is added in anoverlay fashion to a layer for displaying the top-page mode screen asshown in the bottom portion of FIG. 9.

Axes of the image displayed in the related search mode are heredescribed. The axes of the images displayed in the related search modeinclude mutually perpendicular axes, namely, x axis, y axis and z axis.

The layer for displaying the buttons and the thumbnail images isarranged in parallel with a plane of the x axis and the y axis(hereinafter referred to as an XY plane). The y axis represents avertical direction of the buttons and the thumbnail images while the xaxis represents a horizontal direction of the buttons and the thumbnailimages.

The layer for displaying the thumbnail images of the related contentsrelated to the starting content is arranged over the layer fordisplaying the top-page mode screen with a predetermined distancemaintained therebetween in the direction along the z axis.

The layer for displaying the thumbnail images of the related contentsrelated to the starting content displays, in addition to the thumbnailimages of the related contents, a thumbnail image of the startingcontent, a scale-contracted moving image (thumbnail image of a movingimage) and detailed information of the starting content.

As shown in FIG. 9, the thumbnail image of the starting content arrangedin the layer for displaying the thumbnail image of the related contentand the thumbnail image of the starting content arranged in the layerfor displaying the top-page mode screen have the same positions alongthe x axis and the y axis but are spaced by a layer distance along the zaxis.

In this way, the thumbnail image of the starting content is recognizedat a glance. The user can thus come to grips with the current startingcontent.

A scale-contracted moving image of the starting content (thumbnail imageas a moving image) labeled the letter A in FIG. 9 is displayed at apositive position along the y axis of the thumbnail image of thestarting content arranged in the layer for displaying the thumbnailimage of the related content. The detailed information in text of thestarting content labeled the letter B is displayed at a negativeposition along the x axis at the thumbnail image of the starting contentin the layer for displaying the thumbnail image of the related content.

The thumbnail image of at least one related content related to thestarting content at a predetermined item is arranged along a line inparallel with the x axis at positive positions of the x axis at thethumbnail image of the starting content arranged in the layer fordisplaying the thumbnail image of the related content.

For example, if a performer of the starting content and a performer ofthe related content are the same person, the starting content and therelated content are related to each other by the performer. If the filmdirector of the starting content and the film director of the relatedcontent are the same person, the starting content and the relatedcontent are related to each other by the film director.

An item by which the starting content and the related content arerelated to each other is referred to as a category. If the startingcontent and the related content have the performer in common, thestarting content and the related content are related by the category ofthe performer.

The category by which the starting content and the related content arerelated to each other and specific content of the category are displayedat a negative position along the y axis of the thumbnail images of aplurality of related contents arranged in a line in parallel with the xaxis. More specifically, for example, a performer “aaa” in the startingcontent may also play in the related content. In such a case, thecategory of the performer and the name of the performer “aaa” aredisplayed at negative position along the y axis with respect to thethumbnail images of the plurality of related contents arranged in a linein parallel with the x line.

The thumbnail images of at least one related content in one category aresurrounded by a model representing a group (for example, by arectangular shape with a predetermined color).

The user can differentiate the category at a glance.

At least one model of the related contents in one category arranged inone line is also referred to as line.

When the personal computer is transitioned to the related search mode inresponse to the pressing of the left square bracket key of the keyboardin the input unit 16, the thumbnail image of the starting contentarranged in the layer for displaying the thumbnail image of the relatedcontent is focused.

The focused thumbnail image is displayed in the center of the screen ofthe display 31.

As shown in FIG. 9, the line of sight of the camera serving as areference in the drawing of the model such as the button and thethumbnail image is at a slant angle with respect to the layer in therelated search mode. More specifically, the models such as the buttonsand the thumbnail images are displayed in a manner such that the x, yand z axes are slant with respect to the screen of the display 31.

The rightward looking arrow key of the keyboard in the input unit 16 maybe pressed in the related search mode with one of the thumbnail image ofthe starting content and the thumbnail image of the related contentfocused as shown in FIG. 10. In such a case, a thumbnail image arrangednext to the heretofore focused thumbnail image in the positive directionof the x axis is focused in the layer for displaying the thumbnail imageof the related content in the related search mode. More specifically,focusing shifts across the thumbnail images in the positive directionalong the x axis.

The leftward looking arrow key of the keyboard in the input unit 16 maybe pressed in the related search mode with the thumbnail image of therelated content focused. In such a case, a thumbnail image arranged nextto the heretofore focused thumbnail image in the negative direction ofthe x axis is focused in the layer for displaying the thumbnail image ofthe related content in the related search mode. More specifically,focusing shifts across the thumbnail images in the negative directionalong the x axis.

When focusing shifts across the thumbnail images, a scale-contractedmoving image (thumbnail image as a moving image) of the focusedthumbnail image of the related content is displayed at a position in thepositive direction of the y axis. The moving image of the relatedcontent (thumbnail image as a moving image) having the unfocusedthumbnail image is not displayed.

When focusing is shifted across the thumbnail images, a resultingfocused thumbnail image is displayed in the center of the screen of thedisplay 31.

The upward looking arrow key of the keyboard in the input unit 16 may bepressed in the related search mode. In response, thumbnail images of atleast one related content related to the starting content by a newcategory are arranged in a line along the x axis at a position in thepositive direction of the y axis with respect to the thumbnail images ofat least one related content related to the starting content by apredetermined category arranged in a line along the x axis as shown inFIG. 11.

For example, thumbnail images of at least one related content related tothe starting content by release year are arranged in a line along the xaxis at a position in the positive direction of the y axis with respectto the thumbnail images of at least one related content related to thestarting content by a performer “aaa.”

The upward looking arrow key of the keyboard in the input unit 16 may bepressed in the related search mode, for example. In response, thumbnailimages of the related content related to the starting content bydirector are arranged in a line along the x axis at a position in thepositive direction of the y axis with respect to thumbnail images of atleast one related content respectively related to the starting contentby the performer “aaa” as shown in FIG. 11. Furthermore, thumbnailimages of a plurality of related contents related to the startingcontent by release year are arranged in a line along the x axis at aposition further in the positive direction of the y axis. As shown inFIG. 11, no related content related to the starting content by directoris not present and no corresponding thumbnail image is thus displayed.

The upward looking arrow key of the keyboard in the input unit 16 may bepressed in the related search mode, for example. In response, thumbnailimages of at least one related content respectively related to thestarting content by a new category are arranged in a line along the xaxis. One of the thumbnail images related to the starting content by thenew category is then focused.

The focused thumbnail image is displayed in the center of the screen ofthe display 31.

Similarly, the downward looking arrow key of the keyboard in the inputunit 16 may be pressed in the related search mode, for example. Inresponse, thumbnail images of at least one related contents respectivelyrelated to the starting content by a new category are arranged in a linealong the x axis at a position in a negative direction of the y axiswith respect to the thumbnail images of at least one related contentrespectively related to the starting content by a predetermined categoryarranged in a line along the x axis.

In response to the pressing of the downward looking arrow key of thekeyboard in the input unit 16 in the related search mode, the thumbnailimages of at least one related content respectively related to thestarting content by the new category are thus arranged in a line alongthe x axis. One of the thumbnail images respectively related to thestarting content by the new category is then focused. In this case aswell, the focused thumbnail image is displayed in the center of thescreen of the display 31.

The upward looking arrow key of the keyboard in the input unit 16 may bepressed in the related search mode with the thumbnail images of therelated contents of the plurality of categories displayed. Focusingshifts upward through the thumbnail images in the positive direction ofthe y axis. If the downward looking arrow key of the keyboard in theinput unit 16 is pressed, focusing shifts downward through the thumbnailimages in a negative direction of the y axis.

The enter key of the keyboard in the input unit 16 may be pressed withthe thumbnail image of the related content focused as shown in FIG. 12,for example. In response, the thumbnail image of the related content isselected and the related content is selected. The personal computer istransitioned to the play mode, thereby starting playing the selectedcontent.

If the content is a moving image as shown in FIG. 12, the moving imageis displayed instead of the focused thumbnail image. The moving image isexpanded and displayed.

The left square bracket key of the keyboard in the input unit 16 may bepressed in the related search mode with one of the thumbnail images ofthe related contents focused except the thumbnail image of the startingcontent. The related content of the focused thumbnail image is newlyselected as a starting content as shown in FIG. 13. The layer fordisplaying the thumbnail image of the related content related to thenewly selected starting content is placed over the layer for displayingthe thumbnail image of the previous related content. The layer fordisplaying the thumbnail image of the related content related to thenewly selected starting content is spaced from the layer for displayingthe thumbnail image of the previous related content by a predetermineddistance in the direction of the z axis.

One of the thumbnail images on the layer for displaying the thumbnailimage of the related content related to the newly selected startingcontent is focused.

The images on the layer for displaying the thumbnail images of thepreceding related content are displayed in a translucent state.

The layer for displaying the thumbnail image of the related contentrelated to the newly selected starting content is added as shown in FIG.14. Then, the left square bracket key of the keyboard in the input unit16 may be pressed with one of the thumbnail images of the new relatedcontents focused. In response, focusing shifts to one of the thumbnailimages displayed on the layer where the thumbnail images of the startingcontent of the related content having the preceding focused thumbnailimage are displayed.

The images on the layer displaying the focused thumbnail image aredisplayed in a translucent state.

Focusing thus shifts, causing the resulting focused thumbnail image tobe displayed in the center of the screen of the display 31.

The images on the layer for displaying the preceding focused thumbnailimage are displayed in a translucent state. From among the thumbnailimages including once focused one, one related content different fromthe one selected as the starting content may be selected as a newstarting content. In response, the images on the layer for displayingthe preceding focused thumbnail image are deleted.

More specifically, a past search sequence of the related content in thelayer of the thumbnail image of the content newly selected as thestarting content is deleted.

As shown in FIG. 15, the personal computer is transitioned to thesummary mode if the B key of the keyboard in the input unit 16 ispressed in the related search mode.

In the summary mode, the thumbnail images of the starting contents arearranged from left to right in the order of selection of the startingcontents in a horizontal line on the screen of the display 31.

In the summary mode, the leftmost thumbnail image on the screen is athumbnail image of the starting content selected first, the secondthumbnail image from the left on the screen is a thumbnail image of thesecond starting content selected from the related contents related tothe starting content selected first. The third thumbnail image from theleft on the screen is a thumbnail image of the third starting contentselected from the related contents related to the starting contentselected second.

More specifically, if a left one of two thumbnail images juxtaposed isselected as a starting content, a right one of the two thumbnail imagesis a thumbnail image of a starting content selected from relatedcontents related to the starting content of the left thumbnail image inthe summary mode.

In the summary mode, the thumbnail images consecutively horizontallyarranged are connected by horizontal lines.

In the summary mode, a category as a related item and a specific contentof the category are described between the thumbnail image of the contentselected as a starting content and the thumbnail image of the startingcontent selected from the related contents related to the first startingcontent.

If a P key of the keyboard in the input unit 16 is pressed in thesummary mode, the personal computer is shifted to the overhead-viewmode.

In the overhead-view mode of FIG. 16, the viewpoint of the cameraserving as a reference in the drawing of the three-dimensional model,namely, serving as a reference in the drawing of the buttons and thethumbnail images is withdrawn in a direction away from the model such asthe button and the thumbnail image. More specifically, the cameraretreats.

As shown in FIG. 17, the thumbnail image of the first searched relatedcontent is focused, i.e., the content of the thumbnail image in thetop-page mode is selected as a starting content and the thumbnail imageof the related content searched in accordance with the selected startingcontent is focused. If in this state a right square bracket key (“]”symbol key) of the keyboard in the input unit 16 is pressed, thepersonal computer is transitioned to the top-page mode.

In response to the transition from the related search mode to thetop-page mode, the past search sequence of the related contents isdeleted.

The line of sight of the camera serving as a reference in the drawingthe three-dimensional model is forced to be in alignment with the zaxis.

Focusing shifts to a thumbnail image of a content selected as a startingcontent in the top-page mode prior to transitioning to the relatedsearch mode.

If one of the enter key and the right square bracket key of the keyboardin the input unit 16 is pressed in the play mode as shown in FIG. 18,the playing of the content is quit. The personal computer istransitioned to one of the top-page mode and the related search mode. Ifthe mode prior to the play mode is the top-page mode, the personalcomputer is transitioned to the top-page mode subsequent to the end ofplaying. If the mode prior to the play mode is the related search mode,the personal computer is transitioned to the related search modesubsequent to the end of playing.

If the rightward looking arrow key of the keyboard in the input unit 16is pressed in the summary mode, the thumbnail image to the right of theheretofore focused thumbnail image is focused as shown in FIG. 19.Focusing thus shifts rightward across the thumbnail images.

If the leftward looking arrow key of the keyboard in the input unit 16is pressed in the summary mode, the thumbnail image to the left of theheretofore focused thumbnail image is focused. Focusing thus shiftsleftward across the thumbnail images.

If focusing shifts across the thumbnail images in the summary mode, thefocused thumbnail image is displayed in the center of the screen of thedisplay 31.

If the left square bracket key of the keyboard in the input unit 16 ispressed in the summary mode, the content selected as a starting contentis bookmarked as shown in FIG. 20. More specifically, informationidentifying the content selected as the starting content is stored onthe bookmark database 62. The personal computer is then transitioned tothe top-page mode. When the personal computer is transitioned from thesummary mode to the top-page mode, the past search sequence of therelated contents in the related search mode is deleted.

If one of the right square bracket key and the B key of the keyboard inthe input unit 16 is pressed in the summary mode, the personal computeris transitioned to the related search mode as shown in FIG. 21.Subsequent to transitioning to the related search mode, the personalcomputer deletes thumbnail images of the starting contents displayed inthe selection order of the starting contents from the left, thecategories as the related items and the specific contents of thecategories.

One of the upward looking arrow key, the downward looking arrow key, therightward looking arrow key and the leftward looking arrow key may bepressed with the P key of the keyboard in the input unit 16 remainingpressed in the overhead-view mode. In response, the viewpoint of thecamera serving as a reference in the drawing of the three-dimensionalmodel composed of the buttons and the thumbnail images is then shiftedin one of the positive direction of the x axis, the negative directionof the x axis, the negative direction of the y axis and the positivedirection of the y axis as shown in FIG. 22.

If the P key of the keyboard in the input unit 16 is pressed in theoverhead-view mode, the personal computer is transitioned to the relatedsearch mode as shown in FIG. 23. More specifically, the viewpoint of thecamera returns to the original position from the retreat position.

In this way, the personal computer is transitioned to any of thetop-page mode, the related search mode, the play mode, the summary modeand the overhead-view mode.

If the enter key is pressed in the top-page mode with the thumbnailimage focused, the personal computer is transitioned to the play mode asshown in FIG. 24. The content of the focused thumbnail image starts tobe played.

If the left square bracket key is pressed with the thumbnail imagefocused in the top-page mode, the personal computer is transitioned tothe related search mode. The content of the focused thumbnail image isselected as a starting content. The related contents related to thestarting content are thus searched. The thumbnail images of the relatedcontents are arranged in a layer different from the layer for displayingthe images of the top-page mode.

If the left square bracket key is pressed with the thumbnail image ofthe related content focused in the related search mode, the relatedcontent of the focused thumbnail image is newly selected as a startingcontent. New related contents related to the new starting content arethus searched. The thumbnail image of the new related content isarranged in a layer different from the layer displaying the thumbnailimage of the preceding related content.

If one of the upward looking arrow key and the downward looking arrowkey is pressed in the related search mode, a new related content relatedto the starting content is searched. The thumbnail image of the newlyhit related content is displayed on a per category basis in the layerfor displaying the thumbnail image of the related content of thepreceding category.

If the enter key is pressed in the related search mode, the personalcomputer is transitioned to the play mode. The content of the focusedthumbnail image starts to be played.

If the B key is pressed in the related search mode, the personalcomputer is transitioned to the summary mode. The thumbnail images ofthe starting contents arranged in the selection order in a horizontalline, the categories as related items and the specific contents of thecategories are displayed.

In response to the pressing of the left square bracket key in thesummary mode, the content selected as a starting content is bookmarked,namely, registered in my page.

If the enter key is pressed with the thumbnail image of the bookmarkedcontent focused in my page, the personal computer is transitioned to theplay mode. The content of the focused thumbnail image starts to beplayed.

If the left square bracket key is pressed with the thumbnail image ofthe bookmarked content focused in my page, the personal computer istransitioned to the related search mode. The content of the focusedthumbnail image is selected as a starting content and new relatedcontents related to the starting content are then searched.

The display examples displayed on the display 31 discussed withreference to FIGS. 5 through 23 are described with reference flowchartsof FIGS. 25 through 33.

The display process of the mode determiner 52 is discussed below. Themode determiner 52 performs the display process when the top-page modeis set as a display mode.

FIG. 25 is the flowchart illustrating the display process of thetop-page mode. In step S11, the layer layout determiner 102 in the modelparameter determiner 53 sets one layer by setting 1 to a parameterdetermining the number of layers. In step S12, the layer layoutdeterminer 102 in the model parameter determiner 53 references a modelparameter stored on the model parameter storage 107 to select a layer tobe drawn. The layer layout determiner 102 selects the layer by setting,to a parameter determining the layer to be drawn, a value identifyingthe lowest layer heretofore drawn. The lowest layer is a layer havingthe smallest coordinate value in the z axis.

The top page is displayed on the lowest layer in the related searchmode. When the personal computer is transitioned from the related searchmode to the top-page mode, the top page may be displayed by referencingthe model of the once displayed top-page mode.

In step S12 in a first cycle from the start of the display process, themodel parameter storage 107 stores no model parameter. The layer layoutdeterminer 102 sets a predetermined value as a default value to theparameter determining the layer to be drawn. The predetermined valueidentifies a layer to be newly generated.

The genre-sorted content selector 56 selects the content of the genreselected based on data input from the input controller 51 in response toa user operation applied to the input unit 16. In step S13, the top-pagemodel parameter determiner 104 in the model parameter determiner 53determines, based on the selection results of the content, whether thecontent of the selected genre is selected. If it is determined in stepS13 that the content of the selected genre is not selected, step S13 isrepeated until the content of the selected genre is selected.

If it is determined in step S13 that the content of the selected genreis selected, processing proceeds to step S14. In step S14, the top-pagemodel parameter determiner 104 in the model parameter determiner 53determines the layout of the model of the content selected by thegenre-sorted content selector 56. For example, in step S14, the top-pagemodel parameter determiner 104 determines the layout of the model bysetting, to the parameter describing the layout of the thumbnail imageof the content selected by the genre-sorted content selector 56, a valueidentifying the thumbnail image of the selected content, and valuesindicating positions in the x, y and z axes.

In step S15, the model parameter storage 107 in the model parameterdeterminer 53 stores the determined parameter of the model subsequentthe determination in step S14.

In step S16, the three-dimensional model generator 54 references themodel template data 72, thereby generating a three-dimensional modeldescribed in VRML.

In step S17, the view-point specifier 71 in the mode determiner 52specifies to the display controller 55 the viewpoint of the cameralooking from the z axis on the origin in the three-dimensionalcoordinates of the x, y and z axes.

In step S18, the drawing unit 73 in the display controller 55 draws thethree-dimensional model generated in step S16 from the viewpointspecified in step S17, thereby generating display data for displayingthe three-dimensional model.

In step S19, the display controller 55 causes the display 31 to displaythe three-dimensional model in accordance with the display datagenerated in step S18. Processing returns to step S13.

A display process of the related search mode is described below. Themode determiner 52 performs the display process when the personalcomputer determines the related search mode as the display mode.

FIG. 26 is a flowchart illustrating the display process of the relatedsearch mode. In step S31, a model parameter is determined. The parameterdetermination process in step S31 will be described in detail later withreference to a flowchart of FIG. 27.

In step S32, the three-dimensional model generator 54 references themodel template data 72 based on the determined parameter, and generatesa three-dimensional model described in VRML, for example.

In step S33, the view-point specifier 71 in the mode determiner 52specifies to the display controller 55 a viewpoint of the camera lookingtoward a focused model at a slant angle with respect to the XY planedetermined by the x and y axes in the three coordinates of the x, y andz axes.

In step S34, the drawing unit 73 in the display controller 55 draws thethree-dimensional model generated in step S32 from the viewpointspecified in step S33, thereby generating display data for displayingthe three-dimensional model.

In step S35, the display controller 55 causes the display 31 to displaythe three-dimensional model based on the display data generated in stepS34. Processing returns to step S31.

The model parameter determination process corresponding to step S31 isdescribed below with reference to the flowchart of FIG. 27. In step S51,the layer layout determiner 102 determines whether layer addition isrequested, based on data input from the input controller 51 in responseto a user operation to the input unit 16.

When the thumbnail images of the plurality of contents are displayed onthe top-page mode screen as shown in the top portion of FIG. 9, the usermay specify a single content for selection from among the plurality ofcontents using the input unit 16. In response, the input unit 16 inputsa command to select the content from among the plurality of contents inresponse to the user operation for the thumbnail image displayed on thelayer. The input controller 51 supplies the model parameter determiner53 with data representing the selected content. The layer layoutdeterminer 102 in the model parameter determiner 53 determines whether acommand to add a layer is issued, based on the data input from the inputcontroller 51 in response to the user operation on the input unit 16.For example, if the data representing the selected content is input fromthe input controller 51, the layer layout determiner 102 determines thatthe command to add the layer has been issued.

If it is determined in step S51 that the command to add the layer hasbeen issued, processing proceeds to step S52. In step S52, a layeraddition process is performed.

Subsequent to step S52, processing proceeds to step S53.

If it is determined in step S51 that the layer addition command has notbeen issued, processing proceeds to step S53 with step S52 skipped.

In step S53, the focus position determiner 101 determines whether acommand to focus on the model of the related content has been issued,based on data input from the input controller 51 in response to the useroperation on the input unit 16. If it is determined in step S53 that acommand to focus on the model of the related content has been issued,processing proceeds to step S54. A focused display process of the modelof the related content is performed.

Processing proceeds to step S55 subsequent to step S54.

If it is determined in step S53 that no command to focus on the model ofthe related content has been issued, processing proceeds to step S55with step S54 skipped.

In step S55, the related search model parameter determiner 105determines whether a command to display the model of a related contentof a next category has been issued, based on data input from the inputcontroller 51 in response to the user operation on the input unit 16. Ifit is determined in step S55 that a command to display the model of arelated content of a next category has been issued, processing proceedsto step S56. Step S56 is a line addition process of a line along whichmodels of the next category is displayed.

Processing proceeds to step S57 subsequent step S56.

If it is determined in step S55 that a command to display the model ofthe related content of the next category has not been issued, processingproceeds to step S57 with step S56 skipped.

In step S57, the related search model parameter determiner 105determines whether a command to return to an immediately preceding layerhas been issued, based on data input from the input controller 51 inresponse to the user operation on the input unit 16. If it is determinedin step S57 that a command to return to an immediately preceding layerhas been issued, processing proceeds to step S58. The return process toreturn to the immediately preceding layer is performed, and the modelparameter determination process ends.

If it is determined in step S57 that a command to return to animmediately preceding layer has not been issued, the model parameterdetermination process ends with step S58 skipped.

The focused display process of the model of the related contentcorresponding to step S56 is described below with reference to aflowchart of FIG. 28. In step S71, the focus position determiner 101reads from the model parameter storage 107 the model parameterheretofore used in displaying.

In step S72, the focus position determiner 101 references the modelparameter heretofore used in displaying read from the model parameterstorage 107 and determines a focus position to focus on the model of therelated content specified. More specifically, the focus positiondeterminer 101 identifies the thumbnail image to be focused and thensupplies the related search model parameter determiner 105 with datarepresenting the identified thumbnail image.

In step S73, the moving image model layout determining unit 124 in therelated search model parameter determiner 105 determines the layout ofthe model of a moving image for displaying the moving image of therelated content having the model thereof focused. In step S74, forexample, based on the positions of the focused model in the x axis andthe y axis, the moving image model layout determining unit 124determines the layout of the model of the moving image by adding apredetermined value to the position of the model in the y axis with theposition of the model in the x axis unchanged.

In step S74, the model parameter storage 107 stores the parameters ofthe model determined in steps S72 and S73. The focused display processof the model of the related content is thus completed.

The layer addition process corresponding to step S52 is described belowwith reference to flowcharts of FIGS. 29 through 30. In step S101, thelayer layout determiner 102 references the model parameter heretoforeused in displaying stored on the model parameter storage 107, therebydetermining whether a layer for displaying the model of the startingcontent is present. If it is determined in step S101 that a layer fordisplaying the model of the starting content is present, processingproceeds to step S102. In step S102, the related search model parameterdeterminer 105 identifies the selected starting content based on datainput from the input controller 51 in response to the user operation onthe input unit 16.

In step S103, the layer layout determiner 102 references a parameterindicating a selected layer and a parameter describing the number oflayers and determines whether a layer above the selected layer ispresent in the positive direction of the z axis. If it is determined instep S103 that a layer above the selected layer is present in thepositive direction of the z axis, processing proceeds to step S104. Instep S104, the layer layout determiner 102 deletes the model parameterof the layer above the selected layer, namely, the model parameter ofthe layer placed above the selected layer in the positive direction ofthe z axis.

In step S105, the layer layout determiner 102 deletes the layer abovethe selected layer, namely, the layer placed above the selected layer inthe positive direction of the z axis. In step S105, for example, thelayer layout determiner 102 can delete the layer by subtracting 1 fromthe value of the parameter describing the number of layers.

In step S106, the history storage 58 deletes from the related contentsearch history storage unit 75 the search history of all relatedcontents searched and hit in the search in accordance with the startingcontent on the selected layer.

In step S107, the history storage 58 deletes from the starting contentselection history storage unit 76 the selection history of all relatedcontents searched and hit in the search in accordance with the startingcontent on the selected layer.

Processing proceeds to step S108 subsequent to step S107.

If it is determined in step S103 that no layer is present above theselected layer in the positive direction of the z axis, processingproceeds to step S108 with steps S104 through S107 skipped.

In step S108, the history storage 58 causes the starting contentselection history storage unit 76 to store the selection history of thestarting content. For example, the selection history includes valuesidentifying starting contents, and the order of selection of thestarting contents, and a category according to which a precedingstarting content is selected as a related content if the precedingstarting content is present.

In step S109, the category selector 74 in the related content searcher57 selects a category of the starting content from the items related tothe starting content, such as performer, director, release year, etc.For example, in step S109, the category selector 74 reads the metadataof the starting content from the metadata database 61 and selects oneattribute as the category of the starting content from among attributesof the metadata of the starting content including performer, director,and release year.

In step S110, the related content searcher 57 searches for a relatedcontent having the same category value as the category value of theselected category of the starting content. In step S110, for example,the related content searcher 57 reads the metadata of the content fromthe metadata database 61 and searches for the related content having themetadata of the attribute having the same attribute value as theattribute value (value of the metadata) of the attribute of the metadataselected as the category of the starting content in step S109.

In step S111, the history storage 58 stores the search history of therelated content on the related content search history storage unit 75.For example, in step S111, the history storage 58 stores on the relatedcontent search history storage unit 75 as the search history a valueidentifying the hit related content and a value identifying the startingcontent.

In step S112, the related search model parameter determiner 105 in themodel parameter determiner 53 reads from the model parameter storage 107the model parameter heretofore used in displaying.

In step S113, the transparency determiner 103 in the model parameterdeterminer 53 sets the parameter of the degree of transparency of themodel heretofore used in displaying to translucence.

In step S114, the layer layout determiner 102 in the model parameterdeterminer 53 adds a layer above the selected layer in the positivedirection of the z axis. For example, in step S114, the layer layoutdeterminer 102 can add the layer by adding 1 to the value of theparameter describing the number of layers.

In step S115, the layer layout determiner 102 in the model parameterdeterminer 53 selects the added layer. For example, in step S115, thelayer layout determiner 102 can select the added layer by setting, asthe parameter indicating the selected layer, a value indicating thelayer added in step S114.

In step S116, the starting model layout determining unit 121 in therelated search model parameter determiner 105 determines the layout ofthe model of the starting content. For example, in step S116, thestarting model layout determining unit 121 references the positions ofthe thumbnail image of the starting content, arranged in the layerheretofore selected, in the x, y and z axes. The starting model layoutdetermining unit 121 thus sets the x coordinate position and the ycoordinate position of the thumbnail image as the model of the startingcontent in the added layer to be same as the x coordinate position andthe y coordinate position in the layer heretofore selected. The startingmodel layout determining unit 121 sets the z coordinate position of thethumbnail image as the model of the starting content in the added layerto be spaced from the z coordinate position in the layer heretoforeselected by a layer distance. The starting model layout determining unit121 thus determines the layout of the thumbnail image as the model ofthe starting content in the added layer.

The z coordinate position of each layer is described by the respectiveparameter or the distance between layers in the z axis is predetermined.

In step S117, the focus position determiner 101 determines the positionof focus in order to focus on the model of the starting content.

In step S118, the related model structure and layout determining unit122 in the related search model parameter determiner 105 determines thestructure and the layout of the model of the related contents withreference to the position of the model of the starting content so thatthe models of the starting content and the models of the relatedcontents are arranged in a line. For example, in step S118, the relatedmodel structure and layout determining unit 122 determines the numberand order of thumbnail images of the related contents and the positionof each thumbnail image with reference to the position of the model ofthe starting content so that the models of the starting content and themodels of the related contents are arranged in a line.

In step S119, the detailed information model layout determining unit 123in the related search model parameter determiner 105 determines thelayout of the model of the detailed information of the starting contentbased on the position of the model of the starting content. For example,in step S119, the detailed information model layout determining unit 123determines the x, y and z coordinate positions of the model of the textas the detailed information of the starting content labeled the letter Bin FIG. 9 based on the x, y and z coordinate positions of the thumbnailimage of the starting content.

In step S120, the moving image model layout determining unit 124 in therelated search model parameter determiner 105 determines the layout ofthe model of the moving image for displaying the moving image of thestarting content based on the position of the model of the startingcontent. For example, in step S120, the moving image model layoutdetermining unit 124 determines the x, y and z coordinate positions ofthe model of the moving image of the starting content labeled the letterA in FIG. 9 with respect to the x, y and z coordinate positions of thethumbnail image of the starting content.

In step S121, the model parameter storage 107 stores the parameters ofthe model determined heretofore. The layer addition process is thuscompleted.

If it is determined in step S101 that no layer for displaying the modelof the starting content is present, the layer addition process ends withsteps S102 through S121 skipped.

The line addition process corresponding to step S56 is described belowwith reference to a flowchart of FIG. 31. In step S141, the relatedsearch model parameter determiner 105 in the model parameter determiner53 reads from the model parameter storage 107 the parameter of the modelheretofore used in displaying.

In step S142, the related search model parameter determiner 105determines whether a line is present above or below the selected line inthe positive direction or the negative direction of the y axis. If it isdetermined in step S142 that a line is present above or below theselected line, processing proceeds to step S143. In step S143, thecategory selector 74 in the related content searcher 57 selects a newcategory. For example, in step S143, the category selector 74 reads themetadata of the starting content from the metadata database 61 and newlyselects one attribute from the attributes not yet selected as acategory, namely, the attributes of the metadata of the starting contentincluding performer, director, and release year.

In step S144, the related content searcher 57 searches for a relatedcontent having the same category value as the one of the selectedcategory of the starting content. For example, in step S144, the relatedcontent searcher 57 reads from the metadata database 61 the metadata ofthe content and searches for a related content having the metadata asthe attribute having the same attribute value as the one of theattribute of the metadata selected as a category of the starting contentin step S143.

In step S145, the history storage 58 stores the search history of therelated content on the related content search history storage unit 75 inthe same ways as in step S111.

In step S146, the related model structure and layout determining unit122 of the related search model parameter determiner 105 determines thestructure and layout of the model of the related content to be added,based on the position of the model heretofore used in displaying so thatthe models of the new related contents and the models of the previousrelated contents are juxtaposed.

More specifically, in step S146, the related model structure and layoutdetermining unit 122 determines the position of each thumbnail image ofeach related content to be added, based on the position of the modelheretofore used in displaying so that a line of the models of the newrelated contents and a line of the models of the previous relatedcontents are arranged in parallel with each other.

In step S147, the model parameter storage 107 stores the model parameterdetermined in step S146. The line addition process is thus completed.

FIG. 32 is a flowchart illustrating a return process to return to theimmediately preceding layer performed in step S58. In step S161, therelated search model parameter determiner 105 in the model parameterdeterminer 53 reads from the model parameter storage 107 the modelparameter heretofore used in displaying.

In step S162, the transparency determiner 103 in the model parameterdeterminer 53 sets the parameter of the degree of transparency of themodel in the selected layer to translucence.

In step S163, the layer layout determiner 102 in the model parameterdeterminer 53 newly selects a layer immediately below the selected layerin the negative direction of the z axis. For example, in step S163, thelayer layout determiner 102 selects the layer immediately below theselected layer by setting to the parameter indicating the selected layera value indicating the layer immediately below the selected layer.

In step S164, the transparency determiner 103 in the model parameterdeterminer 53 sets the parameter of the degree of transparency of themodel in the newly selected layer to translucence.

In step S165, the model parameter storage 107 stores the parameters ofthe models determined in steps S162 through S164. The return process toreturn to the immediately preceding layer is thus completed.

A display process of the summary mode is described below with referenceto a flowchart of FIG. 33. In step S181, the layer layout determiner 102reads from the model parameter storage 107 the model parameterheretofore used in displaying.

In step S182, the layer layout determiner 102 adds a layer perpendicularto the line of sight of the viewpoint of the camera, above the selectedlayer in the positive direction of the z axis. For example, in stepS182, the layer layout determiner 102 adds the layer perpendicular tothe line of sight of the viewpoint of the camera by adding 1 to thevalue of the parameter describing the number of layers and setting, tothe parameter describing the layout of the layer with respect to the x,y and z axes, a value presenting a position perpendicular to the line ofsight of the viewpoint of the camera.

In step S183, the layer layout determiner 102 selects the layer added instep S182. For example, in step S183, the layer layout determiner 102selects the added layer by setting to the parameter indicating theselected layer a value indicating the layer added in step S182.

In step S184, the summary model parameter determiner 106 reads theselection history of the starting content from the starting contentselection history storage unit 76 in the history storage 58. In stepS185, the summary model parameter determiner 106 arranges the models ofthe starting content, namely, the thumbnail images of the startingcontent in the order of selection in a horizontal line on the screen ofthe display 31.

In step S186, the summary model parameter determiner 106 arranges amodel indicating a category between the models of the starting contents,namely, between the thumbnail images of the starting contents.

In step S187, the three-dimensional model generator 54 references themodel template data 72 in accordance with the determined parameter, andgenerates a three-dimensional model described in VRML.

In step S188, the view-point specifier 71 in the mode determiner 52specifies to the display controller 55 the viewpoint of the camerahaving the line of sight perpendicular to the layer added in step S182and looking toward a focused model at a slant angle with respect to theXY plane determined by the x and y axes in the three coordinates of thex, y and z axes.

In step S189, the drawing unit 73 draws the three-dimensional modelgenerated in step S187 from the viewpoint specified in step S188,thereby generating display data for displaying the three-dimensionalmodel.

In step S190, the display controller 55 causes the display 31 to displaythe three-dimensional model based on the display data generated in stepS189. Processing returns to step S187.

Since the model of the starting content and the model of the relatedcontent are displayed in different layers, the user can distinctlyrecognize the relationship between the starting content and the relatedcontent.

FIGS. 34 through 50 illustrate display examples displayed on the display31 in the output unit 17 in response to the user operation applied tothe input unit 16 in each of the top-page mode, the related search mode,the play mode, the summary mode and the overhead-view mode. The inputunit 16 as a touchpanel is overlaid on the display 31. The personalcomputer here is a mobile type computer.

The contents handled here are music.

FIGS. 34 through 37 illustrate transitioning from the top-page modescreen and the top-page mode to another display mode.

When the display process is started, the screen of the top-page mode isdisplayed on the display 31 in the output unit 17 as shown in FIG. 34.Arranged on the top portion of the top-page mode screen are buttons forselecting my page, J-pops, rock, pops, jazz, dance, R&B, soundtrack andother genre. One of the buttons for selecting genre is focused orselected.

The thumbnail images of the content belonging to the genre of the buttonselected or selected, from among the genre buttons, are arranged in ahorizontal line on the bottom portion of the top-page mode screen. Thethumbnail images include an image of a jacket of a phonograph record oran image of liner notes, for example.

When the display process is started, one button is selected in defaultsetting. For example, the genre button for J-pops is selected as shownin FIG. 34.

When the display process is started, the leftmost thumbnail image on thescreen is focused from among the thumbnail images of the contentbelonging to the genre of the default selected button. For example, asshown in FIG. 34, the leftmost thumbnail image on the screen is focusedin default setting from among the thumbnail images of the contentbelonging J-pops genre.

More specifically, when the display process is started, focusing of thebutton for selecting genre becomes invalid, and focusing of thethumbnail image becomes valid.

If the user lightly touches a button area for selecting a desired genreof operation areas of the input unit 16 as a touchpanel arranged on thedisplay 31, namely, taps the button for selecting a desired genre, thetapped button is focused. Focusing thus shifts to the tapped button.

The thumbnail images of the content belonging to the genre of the tappedbutton are arranged in a horizontal line on the bottom portion of thetop-page mode screen.

If any genre button is tapped, focusing of the tapped button becomesvalid while focusing of the thumbnail image becomes invalid.

If the thumbnail image of the content is tapped as shown in FIG. 35, thethumbnail image tapped is focused on the top-page mode screen. In otherwords, focusing shifts to the tapped thumbnail image.

More specifically, if the thumbnail image of the content is tapped,focusing of the genre button becomes invalid while focusing of thethumbnail image becomes valid.

If the user writes the letter V on the area of the thumbnail image of adesired content of the operation areas of the input unit 16 as atouchpanel arranged on the display 31 as shown in FIG. 36, thatthumbnail image is selected. As a result, the content of the thumbnailimage is selected. The personal computer is transitioned to the playmode, thereby starting playing the selected content.

If the content is music in the play mode as shown in the bottom portionof FIG. 36, a comment on the music content is displayed in image andtext instead of the focused thumbnail image, and the music content isthus output from the loudspeaker 32.

If the user draws a clockwise turning circle surrounding an area of thethumbnail image of a desired content of the operation areas of the inputunit 16 as a touchpanel arranged on the display 31 as shown in FIG. 37,the content of the thumbnail image surrounded by the clockwise turningcircle is selected as a starting content. The personal computer istransitioned to the related search mode.

In the same manner as described with reference to FIGS. 9 through 17,the layer for displaying the thumbnail image of the related contentrelated to the starting content is displayed in the related search modein an overlay fashion above the layer for displaying the top-page modescreen as shown in the bottom portion of FIG. 37.

The layer for displaying the thumbnail image of the related contentrelated to the starting content and the layer for displaying thetop-page mode screen are arranged with a predetermined distancepermitted therebetween.

The thumbnail image is surrounded by the clockwise turning circle andthe display mode of the personal computer is transitioned to the relatedsearch mode. The thumbnail image of the starting content arranged in thelayer for displaying the thumbnail image of the related content isfocused.

The focused thumbnail image is displayed in the center of the screen ofthe display 31.

The line of sight of the camera is at a slant angle with respect to thelayer in the related search mode as shown in FIG. 37.

If one of the thumbnail image of the starting content and the thumbnailimage of the related content is tapped in the related search mode, thetapped thumbnail image is focused as shown in FIG. 38. Morespecifically, focusing shifts to the tapped thumbnail image.

When focusing shifts to the tapped thumbnail image, the focusedthumbnail image is displayed in the center of the screen of the display31.

The user continuously may slide the user's finger in touch with thescreen in one of an upward direction and a downward direction startingwith a point within the area of one of the thumbnail image of thestarting content and the thumbnail image of the related content of theoperation areas of the input unit 16 as a touchpanel arranged on thedisplay 31. In other words, if the user drags across one of thethumbnail image of the starting content and the thumbnail image of therelated content in one of an upward direction and a downward direction,thumbnail images of one or a plurality of related contents respectivelyrelated to the starting content in a new category are arranged in a lineas shown in FIG. 39. The thumbnail images of the related contents in thenew category are displayed in parallel with the thumbnail images of oneor a plurality of related contents related to the starting content inthe predetermined category.

The categories in the music content include genre, first releaselocation, songwriter, composer, producer, label, co-performer, recordingstudio, etc.

If the user writes the letter V on the area of the thumbnail image of adesired content of the operation areas of the input unit 16 as atouchpanel arranged on the display 31 as shown in FIG. 40, thatthumbnail image is selected. As a result, the content of the thumbnailimage is selected. The personal computer is transitioned to the playmode, thereby starting playing the selected content.

If the user draws in the related search mode a clockwise turning circlesurrounding an area of any thumbnail image of a related content, exceptan area of the thumbnail image of the starting content, on the operationareas of the input unit 16 as a touchpanel arranged on the display 31 asshown in FIG. 41, the content of the thumbnail image surrounded by theclockwise turning circle is selected as a new starting content. Thelayer for displaying the thumbnail image of the related content relatedto the newly selected starting content is added above the layer fordisplaying the thumbnail image of the previous related content in anoverlay fashion.

One of the thumbnail images on the layer for displaying the thumbnailimage of the related content related to the newly selected startingcontent is focused.

As shown in the bottom portion of FIG. 41, the image on the layer fordisplaying the thumbnail image of the preceding related content isdeleted. A solid line is drawn connecting the thumbnail image of thenewly selected starting content to the thumbnail image of theimmediately preceding starting content.

The user can easily learn the immediately preceding the starting contentand the newly selected starting content.

The layer for displaying the thumbnail image of the related contentrelated to the newly selected starting content is now added as shown inFIG. 42. If the user now draws a counterclockwise turning circlesurrounding an area of any thumbnail image of the newly selectedstarting content on the operation areas of the input unit 16 as atouchpanel arranged on the display 31, focusing shifts to the layer fordisplaying the thumbnail image of the immediately preceding startingcontent and the thumbnail image of the related content related to theimmediately preceding starting content. The image on the layer fordisplaying the thumbnail image of the related content related to thenewly selected starting content is deleted.

If the user draws in the related search mode a line extending leftdownward on the operation areas of the input unit 16 as a touchpanelarranged on the display 31 starting at a point on the top right cornerof the display 31 as shown in FIG. 43, the personal computer istransitioned to the summary mode.

In the summary mode, the thumbnail images of the starting content aredisplayed in a horizontal line on the screen of the display 31 in theselection order from left to right as shown in the bottom portion ofFIG. 43.

In the summary mode, the leftmost thumbnail image on the screen is athumbnail image of the first selected starting content, and the secondthumbnail image from the left is a thumbnail image of a starting contentselected from the related contents related to the first selectedstarting content, namely, a thumbnail image of a second selectedstarting content. The third thumbnail image from the left on the screenis a thumbnail image of a starting content selected from the relatedcontents related to the second selected starting content, namely, athumbnail image of a third selected starting content.

If a left one of two thumbnail images juxtaposed is selected as astarting content, a right one of the two thumbnail images is a thumbnailimage of a starting content selected from related contents related tothe starting content of the left side thumbnail image in the summarymode.

In the summary mode, the thumbnail images consecutively horizontallyarranged are connected by horizontal lines.

In the summary mode, a category as a related item and a specific contentof the category are described between the thumbnail image of the contentselected as a starting content and the thumbnail image of the startingcontent selected from the related contents related to the first startingcontent.

If the P key of the keyboard in the input unit 16 is pressed in thesummary mode, the personal computer is shifted to the overhead-viewmode.

In the overhead-view mode of FIG. 44, the viewpoint of the camera iswithdrawn in a direction away form the model such as the button and thethumbnail image. More specifically, the camera is retreated. Also, theposition of the viewpoint of the camera is shifted in accordance with adirection of drag.

If the user draws in the related search mode a counterclockwise turningcircle surrounding an area of the thumbnail image of the first selectedstarting content, on the operation areas of the input unit 16 as atouchpanel arranged on the display 31 as shown in FIG. 45, the personalcomputer is transitioned to the top-page mode.

With reference to FIG. 45, the top page is fully displayed on the entirescreen of the display 31 in the top-page mode with the four sides of thetop page in alignment with the four sides of the screen of the display31.

Focusing shifts to the thumbnail image of the content selected as thestarting content in the top-page mode prior to transitioning to therelated search mode.

If the user writes in the play mode the letter V on the operation areasof the input unit 16 as a touchpanel arranged on the display 31 as shownin FIG. 46, the personal computer quits playing the content. Thepersonal computer is transitioned to one of the top-page mode and therelated search mode. If the display mode prior to the play mode is thetop-page mode, the personal computer is transitioned to the top-pagemode subsequent to quitting playing the content. If the display modeprior to the play mode is the related search mode, the personal computeris transitioned to the related search mode subsequent to quittingplaying the content.

If the user taps the thumbnail image in the summary mode, the tappedthumbnail image is focused as shown in FIG. 47. The focused thumbnailimage is displayed in the center of the screen of the display 31.

If the user draws in the summary mode a clockwise turning circle on theoperation areas of the input unit 16 as a touchpanel arranged on thedisplay 31 as shown in FIG. 48, a content selected as a starting contentis registered as a bookmark. The personal computer is transitioned tothe top-page mode. Upon transitioning from the summary mode to thetop-page mode, the personal computer deletes the search track sequenceof the related contents searched heretofore in the related search mode.

If the user draws in the summary mode a straight line extending from atop right point to a bottom left point on the screen of the display 31or a counterclockwise turning circle on the operation areas of the inputunit 16 as a touchpanel arranged on the display 31 as shown in FIG. 49,the personal computer is transitioned to the related search mode. Upontransitioning to the related search mode, the personal computer deletesfrom the screen the thumbnail images of the starting contents arrangedfrom left to right in the selection order of the starting contents, andthe categories as the related items and specific contents of thecategories.

If the user takes his or her finger off the P key of the keyboard in theinput unit 16 in the overhead-view mode, the personal computer istransitioned to the related search mode as shown in FIG. 50. Theviewpoint of the camera returns to the original position thereof, andthe focused thumbnail image is displayed in the center of the screen ofthe display 31.

The tap and drag operations allows the user to shift mode easily and toselect the starting content.

The metadata of the content may be retrieved from another apparatus vianetwork and the communication unit 19.

The search process of the related content is specifically describedbelow.

FIG. 51 is a functional block diagram illustrating another personalcomputer for executing the program. The elements of FIG. 51 areimplemented when the personal computer executes the program. Thepersonal computer includes the input controller 51 controlling the inputunit 16, the mode determiner 52, the model parameter determiner 53, thethree-dimensional model generator 54, the display controller 55controlling the display 31, the genre-sorted content selector 56, therelated content searcher 57, the history storage 58, the player 59, thecommunication controller 60 controlling the communication unit 19, themetadata database 61, the bookmark database 62, and the content database63. The personal computer further includes a related content viewinginformation retrieving unit 201, a viewing information database 202 anda related content display method specifier 203.

In FIG. 51, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The related content searcher 57 retrieves from the metadata database 61the metadata attached to the selected starting content in response todata input from the input controller 51 in response to a user operationapplied to the input unit 16. The related content searcher 57 furtherretrieves from the metadata database 61 the metadata having the samecategory value as the metadata of the starting content but attached to acontent different from the starting content in order to search for therelated content. As a result, the related content searcher 57 retrievesidentification information identifying the related content. Theidentification information identifying the related content is one of acontent name and an ID number.

The related content searcher 57 supplies the related content viewinginformation retrieving unit 201 with the identification informationidentifying the related content.

The related content viewing information retrieving unit 201 retrievesfrom the viewing information database 202 viewing information related toa related content group of related contents searched and hit by therelated content searcher 57. The viewing information database 202 storesthe viewing information as to how much the user has viewed what content,and what content is held by the user.

The related content viewing information retrieving unit 201 retrievesfrom the viewing information database 202 the viewing informationrelated to each related content identified by the identificationinformation.

The related content viewing information retrieving unit 201 supplies theviewing information regarding the related content to the related contentdisplay method specifier 203. The viewing information supplied to therelated content display method specifier 203 indicates how much the userhas viewed each content and what content is held by the user (i.e., whatcontent is stored on the content database 63).

The related content display method specifier 203 determines a displaymethod of each model of the related content falling within the relatedcontent group in accordance with the viewing information regarding therelated content group supplied from the related content viewinginformation retrieving unit 201. The related content display methodspecifier 203 supplies the model parameter determiner 53 withinformation indicating the display method of each model of the relatedcontent.

As shown in FIG. 52A, the related content display method specifier 203determines the display method of the model of the related content sothat the thumbnail image of the related content held by the user isdisplayed in light color and so that the thumbnail image of the relatedcontent not held by the user is displayed in deep color. Alternatively,the related content display method specifier 203 determines the displaymethod of the model of the related content so that the thumbnail imageof the related content viewed by the user is displayed in light colorand so that the thumbnail image of the related content unviewed by theuser is displayed in deep color.

More specifically, the related content display method specifier 203determines the display method of the model of the related content sothat the thumbnail image of the related content held by the user isdisplayed in light color as labeled the letter “b” in FIG. 52A and sothat the thumbnail image of the related content not held by the user isdisplayed in deep color as labeled the letter “e” or “f” in FIG. 52A.

For example, as shown in FIG. 52B, the related content display methodspecifier 203 determines the display method of the model of the relatedcontent so that the thumbnail image of the related content frequentlyviewed by the user is displayed closer to the thumbnail image of thestarting content and so that the thumbnail image of the related contentless frequently viewed by the user is displayed farther from thethumbnail image of the starting content.

More specifically, the related content display method specifier 203determines the display method of the model of the related content sothat the thumbnail image labeled the letter “b” in FIG. 52B of therelated content viewed by twelve times by the user is displayed closerto the thumbnail image labeled the letter “a! in FIG. 52B of thestarting content and so that the thumbnail image labeled the letter “c”in FIG. 52B of the related content viewed by seven times by the user isdisplayed farther from the thumbnail image labeled the letter “a” inFIG. 52B of the starting content.

For example, the related content display method specifier 203 determinesthe display method of the model of the related content as shown in FIG.52C so that the spacing between the thumbnail image of the startingcontent and the thumbnail image of the related content is dependent onthe frequency of viewing of the related content. The related contentdisplay method specifier 203 may determine the display method of themodel of the related content so that the spacing between the thumbnailimage of the starting content and the thumbnail image of the relatedcontent is dependent on the reciprocal number of the frequency ofviewing of the related content.

More specifically, the related content display method specifier 203determines the display method of the model of the related content sothat the spacing between the thumbnail image of the starting content andthe thumbnail image of the related content is dependent on thereciprocal number of the frequency of viewing of the related content,for example, twelve times, eight times or seven times.

For example, the related content display method specifier 203 determinesthe display method of the model of the related content as shown in FIG.52D so that the thumbnail image of the starting content less frequentlyviewed by the user is displayed closer to the thumbnail image of thestarting content and so that the thumbnail image of the starting contentmore frequently viewed by the user is displayed farther from thethumbnail image of the starting content.

FIG. 53 is a flowchart illustrating a process of searching for therelated content and specifying the display method. In step S301, therelated content searcher 57 retrieves the metadata of the startingcontent from the metadata database 61.

In step S302, the related content searcher 57 searches for the relatedcontent in accordance with the metadata of the starting content. Forexample, in step S302, the related content searcher 57 retrieves fromthe metadata database 61 the metadata having the same metadata value inthe same category as the metadata of the starting content but attachedto a content different from the starting content. The related contentsearcher 57 searches for the related content by retrieving theidentification information identifying the related content having themetadata having the same value as the starting content.

In step S303, the related content viewing information retrieving unit201 retrieves from the viewing information database 202 the viewinginformation of the related content searched and hit in step S302. Forexample, in step S303, the related content viewing informationretrieving unit 201 requests the identification information identifyingthe related content as a key from the viewing information database 202and retrieves the viewing information of the related content identifiedby the identification information read from the viewing informationdatabase 202.

In step S304, the related content display method specifier 203 specifiesthe display method of the model of the related content to the modelparameter determiner 53 based on the viewing information retrieved instep S303. The process of searching for the related content andspecifying the display method is thus completed.

The display method of the model such as the thumbnail image is modifieddepending on the content viewing status of the user. The user can easilyfind a new and unviewed content or easily access a familiarized content.

The search process of the related content using similarity is describedbelow.

FIG. 54 is a functional block diagram illustrating another personalcomputer performing a program. The elements of FIG. 54 are implementedwhen the personal computer executes the program. The personal computerincludes the input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computeralso includes a similarity calculator 241 and a related content displaymethod specifier 242.

In FIG. 54, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The similarity calculator 241 calculates similarity between a startingcontent and a related content, thereby determining an arrangement orderof the models of the related contents. The similarity may be cosinedistance, Euclidean distance or the like. The similarity calculator 241supplies the related content display method specifier 242 with thecalculated similarity and information indicating the arrangement orderof the related contents.

For example, the similarity calculator 241 calculates the similarity ofFIG. 56 based on metadata of FIG. 55.

As shown in FIG. 55, content 1 is a starting content, and contents 2through 5 are related contents. As for the content 1, the metadata 1 hasa value of 7, the metadata 2 has a value of 3, the metadata 3 has avalue of 0, the metadata 4 has a value of 9 and the metadata 5 has avalue of 5.

The values of the metadata 1 of the contents 2 through 5 as the relatedcontents are 5, 4, 6 and 5, the values of the metadata 2 of the contents2 through 5 are 2, 4, 4 and 0, the values of the metadata 3 of thecontents 2 through 5 are 4, 5, 7 and 8, the values of the metadata 4 ofthe contents 2 through 5 are 9, 2, 5 and 6, and the values of themetadata 5 of the contents 2 through 5 are 7, 4, 3 and 8, respectively.

The similarity calculator 241 calculates similarity, namely, thereciprocal number of the Euclidean distance of the contents 2 through 5based on the metadata of FIG. 55. For example, as illustrated in FIG.56, the similarity calculator 241 calculates the Euclidean distance ofthe content 2 and obtains 5.000 here, calculates the Euclidean distanceof the content 3 and obtains 9.220 here, calculates the Euclideandistance of the content 4 and obtains 8.426 here and calculates theEuclidean distance of the content 5 and obtains 9.747 here. Thesimilarity calculator 241 calculates the reciprocal number of theEuclidean distance and handles the results as the similarity.

The similarity calculator 241 determines the arrangement order of themodels of the related contents in the order of large to smallsimilarity, namely, in the order from short to long Euclidean distancefrom the content 1, thus arranges the content 2, the content 4, thecontent 3 and the content 5 in that order.

The related content display method specifier 242 determines the displaymethod of each model of the related content in accordance withinformation indicating the similarity and the arrangement order of therelated contents supplied from the similarity calculator 241. Therelated content display method specifier 242 supplies the modelparameter determiner 53 with the information indicating the displaymethod of each model of the related content.

For example, the related content display method specifier 242 determinesthe display method of the model of the related content so that thethumbnail image of the related content (different from the startingcontent) having a low similarity is displayed in light color and so thatthe thumbnail image of the related content (more similar to the startingcontent) having a high similarity is displayed in deep color.

For example, the related content display method specifier 242 determinesthe display method of the model of the related content so that thethumbnail image of the related content (more similar to the startingcontent) having a high similarity is displayed closer to the thumbnailimage of the starting content and so that the thumbnail image of therelated content (more different from the starting content) having a lowsimilarity is displayed farther from the thumbnail image of the startingcontent.

Depending on similarity, the related content display method specifier242 may change both the color density of the thumbnail image and thedistance between the thumbnail image of the starting content and thethumbnail image of the related content.

FIG. 57 is a flowchart illustrating another process for searching forthe related content and specifying the display method. In step S321, therelated content searcher 57 retrieves the metadata of a starting contentfrom the metadata database 61.

In step S322, the related content searcher 57 searches for the relatedcontent in the same way as in step S302 based on the metadata of thestarting content.

In step S323, the similarity calculator 241 calculates the similaritybetween the metadata of the starting content and the metadata of therelated content based on the metadata of the starting content and themetadata of the related content. For example, in step S323, thesimilarity calculator 241 calculates the similarity between the startingcontent and the related content. The similarity is one of the cosinedistance, the Euclidean distance and the reciprocal number of theEuclidean distance.

In step S324, the related content display method specifier 203 specifiesthe display method of the model of the related content to the modelparameter determiner 53 based on the similarity calculated in step S323.The process of searching for the related content and specifying thedisplay method is thus completed.

Since the models of the related contents, such as the thumbnail images,are displayed in the order of similarity between the related content andthe starting content, the user can easily find a content similar to acurrent content of interest.

The search process of the related content in accordance with userpreference is described below. The search process is based on contentbased filtering (CBF) technique.

FIG. 58 is a functional block diagram illustrating yet another personalcomputer performing a program. The elements of FIG. 58 are implementedwhen the personal computer executes the program. The personal computerincludes the input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computerfurther includes a similarity calculator 261, a user preference database262 and a related content display method specifier 263.

In FIG. 58, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The similarity calculator 261 matches the related content group searchedand hit by the related content searcher 57 with preference informationof the user based on the preference information of the user stored onthe user preference database 262. The term “matches” means to determinesimilarity represented by cosine similarity or the Euclidean distancebetween the preference information described in vector and the metadataof the content described in vector.

The preference information of the user is a total sum of vectors of themetadata of contents evaluated as being favorite by the user.

In other words, the similarity calculator 261 calculates the similaritybetween the related content group and the preference information of theuser. The user preference database 262 stores the preference informationof the user.

For example, the similarity calculator 261 retrieves the preferenceinformation of the user from the user preference database 262 andacquires the metadata of the related content from the related contentsearcher 57. The similarity calculator 261 calculates the similaritybetween the preference information and the related content based on thepreference information of the user and the metadata of the relatedcontent.

For example, the similarity calculator 261 calculates the cosinesimilarity between the preference information and the related content inaccordance with the following equation (1):

$\begin{matrix}{{{Cosine}\mspace{14mu} {similarity}} = {\frac{\overset{\rightarrow}{x} \cdot \overset{\rightarrow}{y}}{{\overset{\rightarrow}{x}} \cdot {\overset{\rightarrow}{y}}} = \frac{\sum\limits_{i}{x_{i}y_{i}}}{\sqrt{\sum\limits_{i}x_{i}^{2}}\sqrt{\sum\limits_{i}y_{i}^{2}}}}} & (1)\end{matrix}$

The letter x having a rightward looking arrow thereabove is a vector xrepresenting the preference information of the user, and the letter yhaving a rightward looking arrow thereabove is a vector y representingthe metadata of the related content as represented in the followingequation (2):

{right arrow over (x)}=(x ₁ , x ₂ , . . . x _(m)), {right arrow over(Y)}=(y ₁ , y ₂ , . . . y _(m))  (2)

where x₁ through x_(m) represent m elements of the preferenceinformation of the user and y₁ through y_(n) represent m pieces ofmetadata of the related content, and m represents a data number ofmetadata attached to the content.

FIG. 59 illustrates a preference vector x, i.e., the preferenceinformation of the user in vector representation. In the vector x as thepreference vector in FIG. 59, metadata 1 corresponding to x₁ has a valueof 5, metadata 2 corresponding to x₂ has a value of 0, metadata 3corresponding to x₃ has a value of 3, metadata 4 corresponding to x₄ hasa value of 3 and metadata 5 corresponding to x₅ has a value of 8.

With reference to FIG. 55, the values of the metadata 1 of the contents2 through 5 as the related contents are 5, 4, 6 and 5, the values of themetadata 2 of the contents 2 through 5 are 2, 4, 4 and 0, the values ofthe metadata 3 of the contents 2 through 5 are 4, 5, 7 and 8, the valuesof the metadata 4 of the contents 2 through 5 are 9, 2, 5 and 6, and thevalues of the metadata 5 of the contents 2 through 5 are 7, 4, 3 and 8,respectively. In accordance with equation (1), the similarity calculator261 calculates the cosine similarity as shown in FIG. 60. Morespecifically, the similarity calculator 261 results in a cosinesimilarity of 0.877 for the content 2, a cosine similarity of 0.804 forthe content 3, a cosine similarity of 0.749 for the content 4 and acosine similarity of 0.921 for the content 5.

The arrangement order of the related contents are determined in thelarge to small cosine similarity order, i.e., the content 5, the content2, the content 3 and the content 4 are arranged in that order. Thesimilarity calculator 261 supplies the related content display methodspecifier 263 with the information indicating the arrangement order ofthe related contents.

The related content display method specifier 263 determines the displaymethod of each model of the related content in accordance with thesimilarity and the information indicating the arrangement order of therelated contents supplied from the similarity calculator 261. Therelated content display method specifier 263 supplies the modelparameter determiner 53 with the information indicating the displaymethod of each model of the related content.

FIG. 61 is a flowchart illustrating another process of searching for therelated content and specifying the display method. In step S341, therelated content searcher 57 retrieves the metadata of the startingcontent from the metadata database 61.

In step S342, the related content searcher 57 searches for the relatedcontent based on the metadata of the starting content in the same way asin step S302.

In step S343, the similarity calculator 261 retrieves from the userpreference database 262 the preference information of the user andcalculates the similarity between the preference information of the userand the related content based on the preference information of the userand the metadata of the related content. For example, in step S343, thesimilarity calculator 261 calculates the cosine similarity as thesimilarity between the preference information of the user and therelated content.

In step S344, the related content display method specifier 263 specifiesthe display method of the model of the related content to the modelparameter determiner 53 based on the similarity calculated in step S343.The process of searching for the related content and specifying thedetailed information is thus completed.

By arranging the model of the content matching the preferenceinformation of the user with higher priority, the content group isviewed in a list from a particular standpoint (metadata). The user caneasily select a preferred content.

A model of a related content recommended by another user can bedisplayed.

FIG. 62 is a functional block diagram illustrating yet another personalcomputer performing a program. The elements of FIG. 62 are implementedwhen the personal computer executes the program. The personal computerincludes the input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computerfurther includes an information retrieving unit 281 for related sourcecontent viewing user, a user viewing information database 282, a userviewing content information retrieving unit 283, a candidate contentselection criterion calculator 284, a candidate content selector 285, acandidate content metadata retrieving unit 286 and a candidate contentdisplay method specifier 287.

In FIG. 62, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The related source content viewing user information retrieving unit 281retrieves information indicating a viewing history of contents by theuser and evaluation of the contents by the user from the user viewinginformation database 282.

The user viewing information database 282 stores the viewing history ofthe contents by the user and the evaluation of the contents by the user.When the viewing history and evaluation of the user are requested withthe user being specified, the user viewing information database 282reads and then outputs the viewing history and evaluation of that user.When the viewing history and evaluation of the user are requested with acontent being specified, the user viewing information database 282 readsand then outputs the viewing history of the specified content by eachuser and the evaluation of the specified content by each user.

For example, the related source content viewing user informationretrieving unit 281 retrieves from the user viewing information database282 the viewing history and evaluation of the starting content by theuser having viewed the starting content. That starting content isindicated by data input from the input controller 51 in response to theuser operation on the input unit 16. The related source content viewinguser information retrieving unit 281 selects one of the user havingviewed the starting content and the user having evaluated the startingcontent as having a high standard and retrieves information identifyingthe selected user.

FIG. 63 illustrates an example of five-level evaluation of the contentsby users. As shown in FIG. 63, the content 5 is ranked as having thehighest evaluation level while the content 1 is ranked as having thelowest evaluation level.

In the evaluation table of FIG. 63, the user 1 ranks the content 1 ashaving level 3, the content 2 as having level 3, the content 3 as havinglevel 5, the content 4 as having level 4 and the content 5 as havinglevel 5.

Similarly, in the evaluation table of FIG. 63, the user 2 ranks thecontent 1 as having level 2, the content 2 as having level 3, thecontent 3 as having level 4, the content 4 as having level 2 and thecontent 5 as having level 2.

Also, in the evaluation table of FIG. 63, the user 3 ranks the content 1as having level 3, the content 2 as having level 5, the content 3 ashaving level 2, the content 4 as having level 2 and the content 5 ashaving level 1. In the evaluation table of FIG. 63, the user 4 ranks thecontent 1 as having level 5, the content 2 as having level 1, thecontent 3 as having level 4, the content 4 as having level 5 and thecontent 5 as having level 1.

For example, if the content 3 of FIG. 63 is a starting content, therelated source content viewing user information retrieving unit 281retrieves the evaluation values of the related contents listed in FIG.63 from the user viewing information database 282, and selects the users1, 2 and 4 having ranked the content 3 as having level 4 or higher. Therelated source content viewing user information retrieving unit 281retrieves information identifying the users 1, 2 and 4, such as the username or the user ID.

The related source content viewing user information retrieving unit 281supplies the user viewing content information retrieving unit 283 withthe information identifying the users thus selected.

The user viewing content information retrieving unit 283 retrieves fromthe user viewing information database 282 the evaluation values of thecontents viewed and evaluated by the users selected by the relatedsource content viewing user information retrieving unit 281. The userviewing content information retrieving unit 283 supplies the candidatecontent selection criterion calculator 284 with the evaluation values ofthe contents viewed and evaluated by the selected users.

The candidate content selection criterion calculator 284 calculates acriterion for selecting the content as a candidate content. Thecandidate content selection criterion calculator 284 supplies thecalculated criterion to the candidate content selector 285. For example,the candidate content selection criterion calculator 284 sets a meanvalue of the evaluation values of the selected users as a criterion forselecting the candidate contents to be applied to all contents viewed bythe selected users.

The candidate content selector 285 selects the candidate contentaccording to the criterion. If the user viewing content informationretrieving unit 283 supplies the evaluation values of the contents bythe users as listed in FIG. 63, the candidate content selector 285 setsas the candidate contents all contents except the content 3, namely, thecontents 1, 4 and 5 highly evaluated by the selected users, namely, theusers 1, 2 and 4.

In this case, contents unviewed by the users may be selected ascandidate contents.

The arrangement order of the candidate contents may be determined by themean evaluation value of the selected candidate contents. For example,in the evaluations of the contents by the users as shown in FIG. 63, themean evaluation value of the content 1 is (3+2+5)/3=3.33, the meanevaluation value of the content 4 is (4+2+5)/3=3.67 and the meanevaluation value of the content 5 is (5+2+1)/3=2.67. The models are thenarranged in the high to low mean evaluation value order, i.e., thecontent 4, the content 1 and the content 5 are arranged in that order.

The selection of the candidate content and the calculation of the meanevaluation value may be performed regardless of user's intervention.

The candidate content selector 285 supplies the candidate contentmetadata retrieving unit 286 with the information identifying theselected candidate content together with the information indicating thearrangement order of the candidate contents.

The candidate content metadata retrieving unit 286 retrieves from themetadata database 61 the metadata of the candidate content in accordancewith the information identifying the candidate contents supplied fromthe candidate content selector 285. The candidate content metadataretrieving unit 286 supplies the candidate content display methodspecifier 287 with the retrieved metadata of the candidate contentstogether with the information indicating the arrangement order of thecandidate contents.

In accordance with the information indicating the arrangement order ofthe candidate contents and the metadata of the candidate contents, thecandidate content display method specifier 287 determines the displaymethod of each model of the candidate contents. The candidate contentdisplay method specifier 287 supplies the model parameter determiner 53with information indicating the display method of each model of thecandidate contents.

As shown in FIG. 64, the thumbnail images of the candidates aredisplayed by displaying the thumbnail images of the related contents.

The candidate content display method specifier 287 may determine thedisplay method of each model of the candidate contents so that thethumbnail image of each candidate content is displayed in light color ordeep color depending on the mean evaluation value.

For example, the candidate content display method specifier 287determines the display method of each model of the candidate contents sothat the thumbnail image of the candidate content having a high meanevaluation value is displayed closer to the thumbnail image of thestarting content and so that the thumbnail image of the candidatecontent having a low mean evaluation value is displayed farther from thethumbnail image of the starting content.

For example, as shown in FIG. 52C, the candidate content display methodspecifier 287 determines the display method of each model of thecandidate contents so that the distance between the thumbnail image ofthe starting content and the thumbnail image of the related contentchanges depending on the mean evaluation value.

FIG. 65 is a flowchart illustrating another process of selecting thecandidate content and specifying the display method. In step S361, therelated source content viewing user information retrieving unit 281retrieves the information regarding the user having viewed the startingcontent from the user viewing information database 282. Morespecifically, in step S361, the related source content viewing userinformation retrieving unit 281 retrieves from the user viewinginformation database 282 the viewing history and evaluation of thecontents by the users having viewed the starting content indicated bydata input from the input controller 51 in response to the useroperation on the input unit 16. The related source content viewing userinformation retrieving unit 281 selects one of the user having viewedthe starting content and the user having evaluated the starting contentas having a high standard and retrieves information identifying theselected user.

In step S362, the user viewing content information retrieving unit 283retrieves the information regarding the content viewed by the selecteduser. For example, in step S362, the user viewing content informationretrieving unit 283 retrieves the evaluation value of the content viewedand evaluated by the user selected in step S361 from the user viewinginformation database 282.

In step S363, the candidate content selection criterion calculator 284calculates the selection criterion of the candidate contents.

In step S364, the candidate content selector 285 selects the candidatecontent according to the selection criterion. The candidate contentmetadata retrieving unit 286 retrieves the metadata of the candidatecontent from the metadata database 61.

In step S365, the candidate content display method specifier 287specifies the display method of each model of the candidate content tothe model parameter determiner 53 based on the evaluation value of thecandidate content or the metadata of the candidate content. The processof selecting the candidate content and specifying the display method isthus completed.

The contents likely to be preferred by the user can be efficientlydisplayed by arranging the models of the candidate contents based on theviewing experience of other users interested in the starting content.

A content in a different domain can be searched as a related content ina cross-domain manner and recommended. The term domain refers to a typeof content. For example, music and movies belong to different domain,and books and television programs are different domains.

Contents in different domains may have different metadata but stillshare in common many pieces of metadata including release year, personsrelated to production, or keywords.

FIG. 66 is a functional block diagram illustrating yet another personalcomputer performing a program. The elements of FIG. 66 are implementedwhen the personal computer executes the program. The personal computerincludes the input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computerfurther includes a starting content metadata retrieving unit 301, another-domain related content selector 302, an other-domain contentmetadata database 303, a related content display method specifier 304and an other-domain content database 305.

In FIG. 66, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The starting content metadata retrieving unit 301 retrieves the metadataof the starting content from the metadata database 61 based on theinformation identifying the starting content supplied from the relatedcontent related content searcher 57. The starting content metadataretrieving unit 301 retrieves from the metadata database 61 the metadataof the starting content indicated by data input from the inputcontroller 51 in response to the user operation on the input unit 16.

If the starting content is music recorded on one compact disk, an IDidentifying the compact disk is supplied from the related contentsearcher 57 to the starting content metadata retrieving unit 301 as theinformation identifying the starting content. As shown in FIG. 67, thestarting content metadata retrieving unit 301 retrieves from themetadata database 61 metadata indicating 1980's as age and metadata as akeyword having a value for melancholiness with reference to the startingcontent as the music recorded on the compact disk identified by album 1as ID. The age and the keyword are the categories of metadata. The ageof the starting content as the metadata indicates 1980's and the keywordof the starting content as the metadata indicates melancholiness.

The starting content metadata retrieving unit 301 supplies the retrievedmetadata of the starting content to the other-domain related contentselector 302.

In accordance with the metadata of the starting content supplied fromthe starting content metadata retrieving unit 301, the other-domainrelated content selector 302 retrieves from the other-domain contentmetadata database 303 metadata of another content in a domain differentfrom the domain of the starting content but in the same category as themetadata of the starting content.

The other-domain content metadata database 303 stores the metadata ofthe other domain.

The other-domain content metadata database 303 stores the metadata ofthe content in the other domain, for example, a movie content. Morespecifically, as shown in FIG. 68, the other-domain content metadatadatabase 303 stores metadata having a value indicating 1980's in an agecategory and metadata having a value indicating comical in a keywordcategory for a content identified by movie 1 as ID, metadata having avalue indicating 1990's in the age category and metadata having a valueindicating melancholiness in the keyword category for a contentidentified by movie 2 as ID and metadata having a value indicating1980's in the age category and metadata having a value indicatingmelancholiness in the keyword category for a content identified by movie3 as ID.

Furthermore, the other-domain content metadata database 303 storesmetadata of contents of the other domain, for example, book contents.More specifically, as shown in FIG. 69, the other-domain contentmetadata database 303 stores metadata having a value indicating 1990'sin the age category and metadata having a value indicating business inthe keyword category for a content identified by book 1 as ID, metadatahaving a value indicating 2000's in the age category and metadata havinga value indicating melancholiness in the keyword category for a contentidentified by book 2 as ID and metadata having a value indicating 1980'sin the age category and metadata having a value indicating environmentalproblem in the keyword category for a content identified by book 3 asID.

The metadata in the age category of the starting content as musicrecorded on one compact disk identified by album 1 as ID has a valueindicating 1980's. The content identified by the movie 1 as ID, thecontent identified by the movie 3 and the content identified by the book3 as ID have the metadata having a value indicating 1980's in the agecategory. More specifically, the metadata in the age category attachedto the starting content identified by ID album 1 has the same value asthe metadata in the age category attached to each of the contentidentified by ID movie 1, the content identified by ID movie 3 and thecontent identified by the ID book 3.

The metadata in the keyword category of the starting content as musicrecorded on one compact disk identified by album 1 as ID has a valueindicating melancholiness. The content identified by the movie 2 as ID,the content identified by the movie 3, and the content identified by thebook 2 as ID have the metadata having a value indicating melancholinessin the keyword category. More specifically, the metadata in the keywordcategory attached to the starting content identified by ID album 1 hasthe same value as the metadata in the keyword category attached to eachof the content identified by ID movie 2, the content identified by IDmovie 3 and the content identified by the ID book 2.

The other-domain related content selector 302 includes a categoryselector 321. The category selector 321 selects a category of therelated content to be searched in a different domain.

The other-domain related content selector 302 searches for a content ina domain different from the domain of the starting content but havingthe value of metadata in the category selected by the category selector321 equal to the value of the metadata in the category of the startingcontent. For example, the other-domain related content selector 302reads from the other-domain content metadata database 303 the metadataof the content in the domain different from the domain of the startingcontent and searches for the content, in the different domain, havingthe metadata of an attribute identical in attribute value to theattribute of the metadata selected as a category of the startingcontent.

The other-domain related content selector 302 supplies the relatedcontent display method specifier 304 with the information identifyingthe related content searched and hit in the search in the differentdomain.

The related content display method specifier 304 determines the displaymethod of each model of the related content in the different domainbelonging to the related content group. The related content displaymethod specifier 304 supplies the model parameter determiner 53 withinformation regarding the display method of each mode of the relatedcontent in the different domain.

For example, the related content display method specifier 304 determinesthe display method of each model of the related content in the differentdomain on a per category basis or on a per domain basis as shown in FIG.70.

The metadata having a value indicating 1980's in the age category andthe metadata having a value indicating melancholiness in the keywordcategory may be attached to the starting content as music recorded on acompact disk identified by album 1 as ID. In that case, the relatedcontent display method specifier 203 determines the display method ofeach model of the related content so that a thumbnail image of a relatedcontent identified by movie 1 as ID and a thumbnail image of a relatedcontent identified by movie 2 as ID are arranged in a line. The relatedcontent identified by movie 1 as ID is the related content in the moviedomain and has the metadata having a value indicating 1980's in the agecategory. The related content identified by movie 2 as ID is the relatedcontent in the movie domain and has the metadata having a valueindicating 1980's in the age category.

The metadata having a value indicating 1980's in the age category andthe metadata having a value indicating melancholiness in the keywordcategory may be attached to the starting content as music recorded onthe compact disk identified by album 1 as ID. In that case, the relatedcontent display method specifier 203 determines the display method ofeach model of the related content so that thumbnail images of relatedcontents identified by book 3 as ID, falling within the book domain, andhaving the metadata having a value indicating 1980's in the age categoryare arranged in a line.

The metadata having a value indicating 1980's in the age category andthe metadata having a value indicating melancholiness in the keywordcategory may be attached to the starting content as music recorded on acompact disk identified by album 1 as ID. In that case, the relatedcontent display method specifier 203 determines the display method ofeach model of the related content so that a thumbnail image of a relatedcontent identified by movie 2 as ID and a thumbnail image of a relatedcontent identified by movie 3 as ID are arranged in a line. The relatedcontent identified by movie 2 is the related content in the movie domainand has the metadata having a value indicating melancholiness in thekeyword category. The related content identified by movie 3 is therelated content in the movie domain and has the metadata having a valueindicating melancholiness in the keyword category.

The metadata having a value indicating 1980's in the age category andthe metadata having a value indicating melancholiness in the keywordcategory may be attached to the starting content as music recorded onthe compact disk identified by album 1 as ID. In that case, the relatedcontent display method specifier 203 determines the display method ofeach model of the related content so that thumbnail images of relatedcontents identified by book 2 as ID, falling within the book domain, andhaving the metadata having a value indicating melancholiness in the agecategory are arranged in a line.

The thumbnail images of the related contents in the movie domain andhaving the same metadata value of the age category as the startingcontent are thus arranged in a line. The thumbnail images of the relatedcontents in the book domain and having the same metadata value of theage category as the starting content are thus arranged in a line. Thethumbnail images of the related contents in the movie domain and havingthe same metadata value of the keyword category as the starting contentare thus arranged in a line. The thumbnail images of the relatedcontents in the book domain and having the same metadata value of thekeyword category as the starting content are thus arranged in a line.The thumbnail images of these four types are displayed in lines parallelto each other.

For example, the related content display method specifier 304 maydetermine the display method of each model of the related contents asshown in FIG. 71 so that thumbnail images of related contents are notsorted by domain but sorted by category and displayed.

The metadata having a value indicating 1980's in the age category andthe metadata having a value indicating melancholiness in the keywordcategory may be attached to the starting content as music recorded on acompact disk identified by album 1 as ID. In that case, the relatedcontent display method specifier 203 determines the display method ofeach model of the related content so that a thumbnail image of a relatedcontent identified by movie 1 as ID, a thumbnail image of a relatedcontent identified by movie 3 as ID, and a thumbnail image of a relatedcontent identified by book 3 as ID are arranged in a line. The relatedcontent identified by movie 1 is the related content in the movie domainand has the metadata having a value indicating 1980's in the agecategory. The related content identified by movie 3 is the relatedcontent in the movie domain and has the metadata having a valueindicating 1980's in the age category. The related content identified bybook 3 is the related content in the book domain and has the metadatahaving a value indicating 1980's in the age category.

The metadata having a value indicating 1980's in the age category andthe metadata having a value indicating melancholiness in the keywordcategory may be attached to the starting content as music recorded on acompact disk identified by album 1 as ID. In that case, the relatedcontent display method specifier 203 determines the display method ofeach model of the related content so that a thumbnail image of a relatedcontent identified by movie 2 as ID, a thumbnail image of a relatedcontent identified by movie 3 as ID, and a thumbnail image of a relatedcontent identified by book 2 as ID are arranged in a line. The relatedcontent identified by movie 1 is the related content in the movie domainand has the metadata having a value indicating melancholiness in thekeyword category. The related content identified by movie 3 is therelated content in the movie domain and has the metadata having a valueindicating melancholiness in the keyword category. The related contentidentified by book 2 is the related content in the book domain and hasthe metadata having a value indicating melancholiness in the keywordcategory.

The thumbnail image in one of the movie domain and the book domain andhaving the same metadata value of the age category as the startingcontent and the thumbnail image in one of the movie domain and the bookdomain and having the same metadata value of the keyword category as thestarting content are arranged in lined parallel to each other.

The other-domain content database 305 stores other domain contents.

FIG. 72 is a flowchart illustrating a process of selecting the relatedcontent and specifying the display method. In step S381, the startingcontent metadata retrieving unit 301 retrieves the metadata of astarting content from the metadata database 61.

In step S382, the other-domain related content selector 302 selects therelated content in another domain based on the metadata of the startingcontent. For example, the other-domain related content selector 302retrieves from the other-domain content metadata database 303 themetadata of the other content in a domain different from the domain ofthe starting content but in the same category as the metadata of thestarting content, in accordance with the metadata of the startingcontent retrieved in step S381. The other-domain related contentselector 302 then selects the content in the domain different from thedomain of the starting content and having the metadata value of theselected category equal to the metadata value of the category of thestarting content.

In step S383, the related content display method specifier 304determines the display method of each model of the related content inthe different domain falling within the related content group andspecifies the display method of each model of the related content to themodel parameter determiner 53. The process of selecting the relatedcontent and specifying the display method is thus completed.

By displaying the different domain contents linked by the metadata, theuser can find a new relationship among the contents.

The contents can be displayed with lines re-arranged.

FIG. 73 is a functional block diagram illustrating yet another personalcomputer performing a program. The elements of FIG. 73 are implementedwhen the personal computer executes the program. The personal computerincludes the input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computerfurther includes a line arrangement order calculator 341 and a relatedcontent display method specifier 342.

In FIG. 73, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The related content searcher 57 retrieves from the metadata database 61the metadata attached to the selected starting content based on datainput from the input controller 51 in response to the user operation onthe input unit 16. In order to search for the related content, therelated content searcher 57 further retrieves from the metadata database61 the metadata attached to the content different from the startingcontent but having the same metadata value and the same category as themetadata attached to the starting content. As a result, the relatedcontent searcher 57 retrieves identification information identifying therelated content. The identification information identifying the relatedcontent may be one of the content name and the ID number.

Contents grouped on a per category basis are referred to as a contentgroup.

FIG. 74 illustrates the metadata of the starting content and the relatedcontent. As shown in FIG. 74, a content identified by the content 1 asID is a starting content and contents identified by the contents 2through 5 as IDs are related contents.

The starting content identified by content 1 as ID has the metadatahaving a value of 1980's in the age category and the metadata having avalue of melancholiness in the keyword category.

The metadata having a metadata value of 1980's in the age category andthe metadata having a metadata value of comical in the keyword categoryare attached to the related content identified by the content 2. Themetadata having a metadata value of 1990's in the age category and themetadata having a metadata value of melancholiness in the keywordcategory are attached to the related content identified by the content3. The metadata having a metadata value of 1980's in the age categoryand the metadata having a metadata value of passion in the keywordcategory are attached to the related content identified by the content4. The metadata having a metadata value of 2000's in the age categoryand the metadata having a metadata value of melancholiness in thekeyword category are attached to the related content identified by thecontent 5.

The related content identified by the content 2 and the related contentidentified by the content 4 are sorted into the same content group,namely, the content group 1 because the two contents have the samemetadata value of 1980's in the age category.

The related content identified by the content 3 and the related contentidentified by the content 5 are grouped into the same content group,namely, the content group 2 different from the content group 1 becausethe two contents have the same metadata value of melancholiness in thekeyword category.

The related content searcher 57 groups the related contents in contentgroups.

The related content searcher 57 supplies the line arrangement ordercalculator 341 with the metadata of the starting content and the relatedcontents, information identifying each of the starting content and therelated contents and information grouping the related contents into thecontent group.

The line arrangement order calculator 341 calculates a value determiningthe arrangement order of the models of the related contents belonging toa content group with respect to the model of the starting content.

For example, on a per content basis, the models of the related contentsare arranged in the order of importance of category of the metadataattached to the starting content. More specifically, there are now 100contents in total. The number of contents having a metadata value of1980's in the age category is now 20 and the number of contents having ametadata value of melancholiness in the keyword category is now 10.Since the number of contents having a metadata value of melancholinessin the keyword category is smaller than the number of contents having ametadata value of 1980's in the age category, the starting content,namely, the content 1 is more characterized by the metadata having thekeyword melancholiness.

The line arrangement order calculator 341 determines the linearrangement order of each model of the related contents so that the lineof the models of the related contents grouped in the content group 1 andthe line of the models of the related contents grouped in the contentgroup 2 are arranged in an appropriate fashion. More specifically,although the metadata having the same keyword melancholiness isattached, the model of the related content belonging to the contentgroup 2 in the keyword category is arranged closer to the model of thestarting content than the model of the related content belonging to thecontent group 1 in the age category.

The line arrangement order calculator 341 may handle the metadataattached to the content as a vector, determine similarity between thestarting content and the related content from the vector of themetadata, calculate the sum or the mean value of the similarities on acontent group basis, and arrange the models of the related contentsbelonging to the content group on a per content group basis in the largeto small sum or the large to small mean value of the similarities.

For example, the line arrangement order calculator 341 may calculate asthe similarity the cosine distance from the starting content as thecontent 1 to each of the contents 2 through 5 based on the metadatalisted in FIG. 55.

Based on the metadata listed in FIG. 55, the line arrangement ordercalculator 341 calculates the cosine distances as shown in FIG. 75. Morespecifically, the line arrangement order calculator 341 results in acosine distance of 0.927 for the content 2, a cosine distance of 0.694for the content 3, a cosine distance of 0.766 for the content 4 and acosine distance of 0.733 for the content 5.

The related content identified by the content 2 as ID and the relatedcontent identified by the content 4 as ID are grouped into the contentgroup 1. The related content identified by the content 3 as ID and therelated content identified by the content 5 as ID are grouped into thecontent group 2. The cosine distance, namely, the sum of thesimilarities between the related content identified by the content 2 andthe related content identified by the content 4, both belonging to thecontent group 1, is 0.927+0.766=1.693. The cosine distance, namely, thesum of similarities between the related content identified by thecontent 3 and the related content identified by the content 5, bothbelonging to the content group 2, is 0.694+0.733=1.427.

Since the sum of similarities of the content group 1, namely 1.693, isgreater than the sum of similarities of the content group 2, namely,1.427, the models of the related contents belonging to the content group1 is arranged closer to the model of the starting content than themodels of the related content belonging to the content group 2.

The related content display method specifier 342 determines the displaymethod of each model of the related contents belonging to the relatedcontent group based on the value indicating the arrangement order of thelines calculated by the line arrangement order calculator 341. Themodels of the related contents are thus displayed in a re-arranged orderon a per content group basis. The related content display methodspecifier 203 supplies the model parameter determiner 53 with theinformation indicating the display method of each model of the relatedcontents.

As shown in FIG. 76, the line of the models of the related contentsbelonging to the content group 2 in the keyword category may be arrangedcloser to the model of the starting content than the line of the modelsof the related contents belonging to the content group 1 in the agecategory. In such a case, the lines are re-arranged and displayed asshown in FIG. 77 so that the line of the models of the related contentsbelonging the content group 1 in the age category is arranged closer tothe model of the starting content than the line of the models of therelated contents belonging to the content group 2 in the keywordcategory.

The lines of the content groups may be spaced from the model of thestarting content by a distance responding to one importance andsimilarity.

FIG. 78 is a flowchart illustrating a process of searching for therelated content and specifying the display method. In step S401, therelated content searcher 57 retrieves the metadata of the startingcontent from the metadata database 61. In step S402, the related contentsearcher 57 searches for the starting content based on the metadata ofthe starting content in the same manner as in step S302.

In step S403, the line arrangement order calculator 341 calculates thearrangement order on a per content group basis. For example, the linearrangement order calculator 341 calculates the line arrangement orderon a per content group basis based on the importance of the metadata ofthe category. Furthermore, the line arrangement order calculator 341 maycalculate the line arrangement order on a per content group basis basedon the sum or the mean value of the similarities of the models of thecontent group.

In step S404, the related content display method specifier 342 specifiesto the model parameter determiner 53 the display method of each model ofthe related content based on the arrangement order calculated in stepS403. The process of searching for the related content and specifyingthe display method is thus completed.

The more closely the model of the related content is related to thestarting content, the closer the model of the related content isarranged to the model of the starting content. The user can thus easilyvisibly recognize the relationship between the starting content and therelated content. Each content is easily selected.

The selection history of the related content may be stored and from theselection history, a playlist for commanding a content to be played maybe produced.

FIG. 79 is a functional block diagram illustrating yet another personalcomputer performing a program. The elements of FIG. 79 are implementedwhen the personal computer executes the program. The personal computerincludes the input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computerfurther includes a metadata list retrieving unit 361, a search historydatabase 362 and a content group selector 363.

In FIG. 79, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The related content searcher 57 retrieves from the metadata database 61the metadata attached to the selected starting content based on datainput from the input controller 51 in response to the user operation onthe input unit 16. In order to search for the related content, therelated content searcher 57 further retrieves from the metadata database61 the metadata attached to the content different from the startingcontent but having the same metadata value and the same category as themetadata attached to the starting content. As a result, the relatedcontent searcher 57 retrieves identification information identifying therelated content. The identification information identifying the relatedcontent may be one of the content name and the ID number.

When a next starting content is selected from the related contents, therelated content searcher 57 causes the search history database 362 tostore, as a search history, metadata linking the selected next startingcontent to the immediately preceding starting content.

For example, when the next starting content is selected form the relatedcontents, the related content searcher 57 causes the search historydatabase 362 to store the metadata common to the selected next startingcontent and the immediately preceding starting content, namely, metadatahaving the same category and the same category value out of the metadataattached to both the selected next starting content and the immediatelypreceding starting content.

The search history database 362 stores the metadata linking the startingcontent and the starting content newly selected from the relatedcontents related to the first starting content. More specifically, thesearch history database 362 stores the metadata common to both thestarting content and the starting content newly selected from therelated contents related to the first starting content in a manner suchthat the common metadata is associated with the starting content and thenewly selected starting content. In other words, the metadata having thesame category and the same category value out of the metadata attachedto both the selected next starting content and the immediately precedingstarting content is stored in association with the starting content andthe newly selected starting content.

The search history database 362 stores as a session a metadata groupused in the searching of a series of related contents. For example, thesession may be defined as a predetermined period of time with respect toa user action of issuing a search command or a predetermined number ofcontents. The search history database 362 stores one of the order of thestarting contents and the order of the related contents and one of themetadata of the starting content and the metadata of the related contentwithin the session on a per session basis.

FIG. 80 illustrates an example of metadata to be stored on the searchhistory database 362 and linking the successively selected relatedcontents and the starting content.

As shown in FIG. 80, a related content related to a starting contentlabeled 1 is searched and hit in accordance with the starting contentlabeled 1, a starting content labeled 2 is selected from the relatedcontents, related contents related to the starting content labeled 2 aresearched and hit in accordance with the starting content labeled 2, anda starting content labeled 3 is selected from the related contents.Related contents related to the starting content labeled 3 are searchedand hit in accordance with the starting content labeled 3, and astarting content labeled 4 is selected from the related contents. Thestarting content labeled 1, the starting content labeled 2, the startingcontent labeled 3 and the starting content labeled 4 are arranged inthat order from the left.

As shown in FIG. 80, the metadata value in the age category of themetadata linking the starting content labeled 1 to the starting contentlabeled 2 is 1980's. The metadata value in the genre category of themetadata linking the starting content labeled 2 to the starting contentlabeled 3 is rock. The metadata value in the mood category of themetadata linking the starting content labeled 3 to the starting contentlabeled 4 is rhythmic.

More specifically, the metadata in the same category and having the samemetadata as the metadata having a metadata value of 1980's in the agecategory attached to the starting content labeled 1 is also attached tothe attached to the starting content labeled 2. The metadata in the samecategory and having the same metadata as the metadata having a metadatavalue of rock in the genre category attached to the starting contentlabeled 2 is also attached to the attached to the starting contentlabeled 3. Furthermore, the metadata in the same category and having thesame metadata as the metadata having a metadata value of rhythmic in themood category attached to the starting content labeled 3 is alsoattached to the attached to the starting content labeled 4.

In this way, the related contents related to the starting contentlabeled 1 are searched and hit in accordance with the starting contentlabeled 1, the starting content labeled 2 is selected from the relatedcontents, the related contents related to the starting content 2 aresearched and hit in accordance with the starting content labeled 2, andthe starting content labeled 3 is selected from the related contents.The related contents related to the starting content labeled 3 aresearched and hit in accordance with the starting content labeled 3, andthe starting content labeled 4 is selected from the related contents.The search history database 362 stores the metadata with the respectivestarting contents associated therewith. The stored metadata include themetadata having a metadata value of 1980's in the age category linkingthe starting content labeled 1 to the starting content labeled 2, themetadata having a metadata value of rock in the genre category linkingthe starting content labeled 2 and the starting content labeled 3, themetadata having a metadata value of rhythmic in the mood categorylinking the starting content labeled 3 to the starting content labeled4.

More specifically, the search history database 362 stores the session IDidentifying the session, the order within the session, the category, andthe metadata value in association with each other. As shown in FIG. 81,the search history database 362 associates the session ID having 1, theorder within the session having 1, the age as the category, and 1980'sas the metadata value in association with each other. The search historydatabase 362 associates the session ID having 1, the order within thesession having 2, the genre as the category, and rock as the metadatavalue in association with each other. The search history database 362associates the session ID having 1, the order within the session having3, the mood as the category, and rhythmic as the metadata value inassociation with each other.

The metadata list retrieving unit 361 retrieves the search history of anappropriate session from the search history database 362. The sessionfor retrieving the search history may be selected based on data inputfrom the input controller 51 in response to the user operation on theinput unit 16. Alternatively, the session for retrieving the searchhistory may be the one having at the head thereof the metadata attachedto the starting content currently being played or the starting contentwith the model thereof being displayed.

The search history of the appropriate session retrieved from the searchhistory database 362 by the metadata list retrieving unit 361 isreferred to as a metadata list.

The metadata list retrieving unit 361 supplies the metadata list to thecontent group selector 363.

The content group selector 363 retrieves from the metadata database 61the metadata matching the metadata list supplied from the metadata listretrieving unit 361 and links the contents in order to fit the metadatainto the metadata list. Since there are typically a plurality ofcontents having a predetermined metadata value in a predeterminedcategory, the metadata matching the metadata list cannot be uniquelydetermined.

The metadata may be randomly determined or the metadata of a contentgroup sharing metadata unrelated to the metadata list may be selected.In this way, the metadata may be selected based on some sort ofsimilarity.

If the search history of FIG. 81 is selected as a metadata list, thecontent group selector 363 retrieves from the metadata database 61 themetadata of FIG. 82. As shown in FIG. 82, the content group selector 363retrieves the metadata from the metadata database 61. More specifically,the content group selector 363 retrieves from the metadata database 61metadata having a metadata value of 1980's in the age category andmetadata having a metadata value of rock in the genre category attachedto a content identified by content 6 as ID. The content group selector363 retrieves from the metadata database 61 metadata having a metadatavalue of rock in the genre category and metadata having a metadata valueof rhythmic in the mood category attached to a content identified bycontent 9 as ID. The content group selector 363 retrieves from themetadata database 61 metadata having a metadata value of melancholinessin the keyword category and metadata having a metadata value of 1980'sin the age category attached to a content identified by content 12 asID. The content group selector 363 retrieves from the metadata database61 metadata having a metadata value of rhythmic in the mood category andmetadata having a metadata value of 2000's in the age category attachedto a content identified by content 17 as ID.

As shown in FIG. 81, the starting contents are linked in the metadatalist by the metadata having a metadata value of 1980's in the agecategory, the metadata having a metadata value of rock in the genrecategory and the metadata having a metadata value of rhythmic in themood category. As shown in FIG. 83, the content group selector 363selects the contents so that the metadata fits in the metadata list. Thecontent group selector 363 selects the content identified by content 12as ID, the content identified by content 6 as ID, the content identifiedby content 9 as ID and the content identified by content 17 as ID inthat order. More specifically, the content group selector 363 selectsthe contents in the following order: the content with the metadatahaving a metadata value of 1980's in the age category, the content withthe metadata having a metadata value of 1980's in the age category andthe metadata having a metadata value of rock in the genre category, thecontent with the metadata having a metadata value of rock in the genrecategory and the metadata having a metadata value of rhythmic in themood category, and the content with the metadata having a metadata valueof rhythmic in the mood category.

The models of the contents linked in accordance with the metadata listmay be displayed in the same way as the models of the related contents.Optionally, the contents linked in accordance with the metadata list maybe displayed using arrow-headed lines as shown in FIG. 84.

FIG. 85 is a flowchart illustrating a search process of the relatedcontent. In step S421, the related content searcher 57 retrieves themetadata of the starting content from the metadata database 61. In stepS422, the related content searcher 57 searches for the related contentin accordance with the metadata of the starting content. For example, instep S422, the related content searcher 57 retrieves from the metadatadatabase 61 the metadata having the same metadata value as the metadataattached to the starting content but attached to a content differentfrom the starting content. In order to search for the related content,the related content searcher 57 retrieves identification informationidentifying the related content to which the metadata identical to themetadata of the starting content is attached.

In step S423, the search history database 362 stores the search historysupplied from the related content searcher 57. The search process of therelated content is thus completed.

For example, in step S423, the search history database 362 stores thesearch history containing the session ID identifying the session, theorder within the session, the category and the metadata value with eachassociated with the other.

FIG. 86 is a flowchart illustrating a display process of the relatedcontent. In step S441, the metadata list retrieving unit 361 retrievesthe metadata list from the search history database 362. For example, instep S441, the metadata list retrieving unit 361 retrieves from thesearch history database 362 as the metadata list the search historyrelated to a current session or a session specified by the user.

In step S442, the content group selector 363 selects a content groupbased on the metadata list retrieved in step S441 and the metadataretrieved from the metadata database 61. For example, in step S442, thecontent group selector 363 selects a content having the metadatamatching the metadata list and links the selected contents. The contentgroup selector 363 thus selects the content group.

In step S443, the content group selector 363 specifies to the modelparameter determiner 53 the display method of each model of the contentgroup selected in step S442 based on the metadata list and the metadata.The display process of the related content is thus completed.

A learning process of preference is described below.

FIG. 87 is a functional block diagram of another personal computerperforming a program. The elements of FIG. 87 are implemented when thepersonal computer executes the program. The personal computer includesthe input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computerfurther includes a related content searcher 381 and a preferenceinformation database 382.

In FIG. 87, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The related content searcher 381 retrieves from the metadata database 61the metadata attached to the selected starting content based on datainput from the input controller 51 in response to the user operation onthe input unit 16. The related content searcher 381 searches for therelated content by retrieving from the metadata database 61 the metadataattached to a content different from the starting content but belongingto the same category as the metadata of the starting content. As aresult, the related content searcher 381 retrieves the identificationinformation identifying the related content. The identificationinformation identifying the identification information may be one of thecontent name and the ID number.

When a starting content is selected from among the related contents, therelated content searcher 381 causes the preference information database382 to store, as preference information indicating the preference of theuser, information identifying the selected starting content and themetadata thereof. When a next starting content is selected from amongthe related contents, the related content searcher 381 causes thepreference information database 382 to store, as the preferenceinformation, metadata linking the selected next starting content to theimmediately preceding starting content, information identifying thestarting content, the metadata of the related content and the metadataof the starting content.

The related content searcher 381 includes a category selector 391. Thecategory selector 391 selects a category of the related content searchedand hit by the related content searcher 381.

The preference information database 382 stores, as the preferenceinformation, the metadata linking the selected next starting content tothe immediately preceding starting content, the information identifyingthe starting content, the metadata of the related content and themetadata of the starting content.

With the metadata of FIG. 55 stored on the metadata database 61, thecontent 1 may be first selected as a starting content and then thecontent 3 may then be selected as a next starting content. The relatedcontent searcher 381 handles the metadata 1 through the metadata 5attached to the content 1 as a vector, and the metadata 1 through themetadata 5 attached to the content 3 as a vector, sums the two vectorsand sets the summing results as the preference information indicatingthe preference of the user. For example, FIG. 88 shows the preferenceinformation as the vectors. The value of the metadata 1 is 11, the valueof the metadata 2 is 7, the value of the metadata 3 is 5, the value ofthe metadata 4 is 11 and the value of the metadata 5 is 9.

The preference information stored on the preference information database382 can be used in any recommendation system. The preference informationcan also be used in the search process of the related content based onthe user's preference previously discussed with reference to FIGS. 58through 61.

FIG. 89 is a flowchart illustrating a storage process of the preferenceinformation. The related content searcher 381 determines in step S461whether a starting content has been selected, based on data input fromthe input controller 51 in response to the user operation on the inputunit 16. If it is determined in step S461 that no starting content hasbeen selected, the determination process in step S461 is repeated untila starting content is selected.

If it is determined in step S461 that a starting content has beenselected, processing proceeds to step S462. In step S462, the relatedcontent searcher 381 causes the preference information database 382 tostore the preference information. Processing returns to step S461subsequent to step S462.

When a next starting content is selected from among the relatedcontents, the related content searcher 381 causes the preferenceinformation database 382 to store the preference information in stepS462. The preference information contains the metadata linking theselected next starting content to the immediately preceding startingcontent, the information identifying the starting content, the metadataof the related content and the metadata of the starting content. If aplurality of starting contents are selected, the related contentsearcher 381 handles the metadata attached to each starting content as avector, sums the values of the metadata for each piece of metadata andcauses the preference information database 382 to store the summingresults as the preference information indicating the user's preference.

This arrangement allows the user to be freed from expressly evaluatingeach content as to whether the user likes the content or not. By simplyperforming search operations, the user can accumulate information forcontent recommendation. Workload on the user is thus reduced.

A process of narrowing and selecting the related content is describedbelow.

FIG. 90 is a functional block diagram of another personal computerperforming a program. The elements of FIG. 90 are implemented when thepersonal computer executes the program. The personal computer includesthe input controller 51 controlling the input unit 16, the modedeterminer 52, the model parameter determiner 53, the three-dimensionalmodel generator 54, the display controller 55 controlling the display31, the genre-sorted content selector 56, the related content searcher57, the history storage 58, the player 59, the communication controller60 controlling the communication unit 19, the metadata database 61, thebookmark database 62, and the content database 63. The personal computerfurther includes a narrowing condition input unit 401 and a narrowingcondition selector 402.

In FIG. 90, elements identical to those illustrated in FIG. 2 aredesignated with the same reference numerals and the discussion thereofis omitted here.

The related content searcher 57 retrieves from the metadata database 61the metadata attached to the selected starting content in response todata input from the input controller 51 in response to a user operationapplied to the input unit 16. The related content searcher 57 furtherretrieves from the metadata database 61 the metadata having the samecategory value as the metadata of the starting content but attached to acontent different from the starting content. The related contentsearcher 57 thus searches for the related content. As a result, therelated content searcher 57 retrieves identification informationidentifying the related content. The identification informationidentifying the related content is one of a content name and an IDnumber.

The related content searcher 57 supplies the narrowing conditionselector 402 with the identification information identifying the relatedcontent as a related content list.

The narrowing condition input unit 401 retrieves metadata for narrowingand selecting the related contents in a process separate from theprocess of selecting the starting content or searching for the relatedcontent and supplies the retrieved metadata to the narrowing conditionselector 402. For example, the narrowing condition input unit 401retrieves the metadata by operating the input unit 16 or receiving themetadata via the communication unit 19. Furthermore, the narrowingcondition input unit 401 can retrieve the metadata by storing metadataspecified beforehand by the user and reading the stored metadata.

Alternatively, the input controller 51 may supply the narrowingcondition selector 402 with the metadata that the user has specifiedusing the input unit 16 as the metadata for narrowing and selecting therelated contents.

With the metadata supplied from the narrowing condition input unit 401as a condition, the narrowing condition selector 402 selects contentsthat satisfy the condition. For example, the narrowing conditionselector 402 selects, from the related contents presented in a list, thecontents having the same metadata as the metadata supplied from thenarrowing condition input unit 401.

FIG. 91 illustrates an example of metadata attached to the content. Asshown in FIG. 91, the content identified by content 1 as ID is astarting content and contents identified by content 2 through 5 as IDsare related contents.

The starting content identified by content 1 has the metadata having ametadata value of 1980's in the age category and the metadata having ametadata value of melancholiness in the keyword category.

The related content identified by content 2 has the metadata having ametadata value of 1980's in the age category and the metadata having ametadata value of melancholiness in the keyword category. The relatedcontent identified by content 3 has the metadata having a metadata valueof 1980's in the age category and the metadata having a metadata valueof comical in the keyword category. The related content identified bycontent 4 has the metadata having a metadata value of 1980's in the agecategory and the metadata having a metadata value of passion in thekeyword category. The related content identified by content 5 has themetadata having a metadata value of 1980's in the age category and themetadata having a metadata value of melancholiness in the keywordcategory.

Age is now selected as a search category of the related contents.Displayed on the display 31 as shown in FIG. 92 are a model of a relatedcontent identified by content 2, a model of a related content identifiedby content 4 and a model of related content identified by content 5,each with the metadata having a metadata value of 1980's in the agecategory.

The narrowing condition selector 402 receives the metadata having ametadata value of melancholiness in the keyword category from thenarrowing condition input unit 401. The narrowing condition selector 402then selects the related content identified by content 2 and the relatedcontent identified by content 5, each with a metadata value ofmelancholiness in the keyword category, from among the related contentsidentified by contents 2, 4 and 5.

With reference to FIG. 93, the display 31 displays a line of the modelsof the related contents selected according to a metadata value ofmelancholiness in the keyword category, namely, a line of the models ofthe related contents identified by contents 2 and 5 in parallel with aline of the models of the related contents identified by contents 2, 4and 5.

As shown in FIG. 93, the line of models of narrowed and selected relatedcontents is labeled with a selected category and a metadata value inthat category and as narrowing and selection conditions a category and ametadata value in that category.

FIG. 94 is a flowchart illustrating a narrowing process of the relatedcontents. In step S481, the narrowing condition input unit 401 retrievesa narrowing condition. For example, in step S481, the narrowingcondition input unit 401 retrieves a narrowing condition composed of acategory of metadata and a metadata value in that category provided inresponse to an instruction from the user.

In step S482, the narrowing condition selector 402 narrows and selectsthe related contents. The process of narrowing and selecting the relatedcontents is thus completed.

For example, in step S482, the narrowing condition selector 402 selects,from among the related contents, the related content having the metadatain the category indicated in the narrowing condition and the metadatavalue indicated in the narrowing condition.

By displaying the models of the contents prior to and subsequent to thenarrowing and selection process in parallel, the user can easily find anappropriate condition in the content search.

Windows and layout may be differentiated not only in two-dimensionaldisplay, but also in both two-dimensional and three-dimensional display.By presenting the modes with two-dimensional and three-dimensional mixeddisplays, function to function shifting can be easily performed. Theuser can intuitively recognize the modes of the contents.

Recommendations provided by the computer are not unilateral but takesinto user's interests. The computer displays information regardingcandidate contents and related contents of interest to the user in aflexible way.

A plurality of contents related to any content are displayed whileinformation about the contents is displayed in a manner such that therelationship of the contents and the grouping of the contents are easilyrecognized.

In the related content search, a second content related to a firstcontent is displayed, and a new content related to the second content isfurther displayed. In such a presentation of the contents, informationis basically continually presented from a starting point from left toright on the display screen. The user can easily come to grips with thecurrent user's operation position on the screen.

A three-dimensional display method is used to introduce a new contentserving as a reference. Layer presentation is used to display contentsin a continual manner but with a distinct delimitation inserted betweenlayers of contents. The user can intuitively learn the structure of thelayout of contents.

The use of the three-dimensional structure eliminates the need fordisplaying related contents to be displayed in a two-dimensional layoutof the same plane in a congested manner. Closely related contents areneatly displayed in a close location without any difficulty.

Information regarding a content related to any other content isdisplayed along with a predetermined pieces of information of contentsfor comparison purposes. The user can thus enjoy selecting a contentlike selecting a content while viewing a catalog as the user's interestshifts, and then feel convinced with the selection results.

Since a plurality of related contents are displayed, an unviewed contentcan be mixed with viewed contents. This serves as an incentive to theuser's feeling to view all contents and thus draws the user's interestin the contents.

Since three-dimensional depth is given to content information display,the user feels that each content has something therewithin rather thansimply mere digital data. The user is thus motivated to be in possessionof and to collect the contents. The user feels that the content deservesthe cost thereof.

The results of repeated related searching are summarized in conjunctionwith relationship of the starting contents and then displayed along withrelation reason. The user can briefly recognize the shifting of theuser's own interest. Since not only the user but also the contentprovider can learn how such interest shifting has been caused, such datamay be used in marketing purposes.

Instead of displaying the thumbnail image of the related content,characters representing the related content such as a title of therelated content may be displayed. The character representing the relatedcontent may be displayed together with the thumbnail image of therelated content.

When the metadata of the content is read and displayed, informationrelating to the content is also displayed. The second content linked tothe first content is searched for and display of a search history ofcontent search is controlled. The content search is performed inaccordance with one of the first image and the first character, eachindicating the first content, one of the second image and the secondcharacter, each indicating the second content and the link informationlinking the first content to the second content. When the contents aretracked, a relation of the tracked contents is viewed and recognized ata glance.

In the above embodiments, the present invention is applied to thepersonal computers. The present invention is applicable to not only thepersonal computer but also a variety of consumer electronics. Theconsumer electronics include mobile devices such as a cellular phone,and stationary devices such as a set-top box and a hard disk recorder.

Another apparatus such as a server may include the metadata database 61,the bookmark database 62, the content database 63, the viewinginformation database 202, the user preference database 262, the userviewing information database 282, the other-domain content metadatadatabase 303, the other-domain content database 305, the search historydatabase 362 and the preference information database 382. A variety ofdata including metadata may be read from or recorded onto the server viaa network and the communication unit 19.

The above-referenced series of steps may be performed using hardware orsoftware.

The program to be executed by the computer may be performed in thetime-series order discussed previously, or may be performed in parallelor may be performed at a timing call is placed.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A display control apparatus comprising: search means for searchingfor a second content linked to a first content; and display controlmeans for controlling display of a search history of content searchperformed in accordance with one of a first image and a first character,each indicating the first content, one of a second image and a secondcharacter, each indicating the second content and link informationlinking the first content to the second content.
 2. The display controlapparatus according to claim 1, wherein the display control meanscontrols the display of the search history of the content searchperformed in accordance with the first image and the second image, eachbeing a thumbnail image, and the link information between the firstcontent and the second content.
 3. The display control apparatusaccording to claim 1, wherein the display control means controls thedisplay of the search history including an image indicating a linkbetween one of the first image and the first character and one of thesecond image and the second character.
 4. The display control apparatusaccording to claim 1, wherein the search means searches for the secondcontent having the same metadata as metadata of the first content. 5.The display control apparatus according to claim 1, wherein the searchmeans searches for a third content linked to the second content, andwherein the display control means controls the display of the searchhistory of the content search performed in accordance with one of thefirst image and the first character, one of the second image and thesecond character, one of a third image and a third character, eachindicating the third content, the link information linking the firstcontent to the second content and link information linking the secondcontent to the third content.
 6. The display control apparatus accordingto claim 1, further comprising generating means for generating athree-dimensional model, the three-dimensional model including a firstlayer having one of the first image and the first character of the firstcontent arranged therewithin, a second layer having one of the secondimage and the second character of the second content arrangedtherewithin and a third layer having one of the first image and thefirst character, one of the second image and the second character andtext indicating the link information between the first content and thesecond content, and wherein using the three-dimensional model, thedisplay control means controls the display of the search history of thecontent search performed in accordance with one of the first image andthe first character, one of the second image and the second characterand the text indicating the link information between the first contentand the second content.
 7. The display control apparatus according toclaim 1, wherein the display control means controls the display of thesearch history of the content search performed in accordance with thelink information indicating both a category related to each of the firstcontent and the second content and a specific content of the category.8. The display control apparatus according to claim 1, wherein thesearch means searches for the second content linked to the first contentin accordance with at least part of metadata attached to each of thefirst content and the second content.
 9. The display control apparatusaccording to claim 1, wherein the display control means controls thedisplay of the search history in a two-dimensional image and controlsthe display of the content search in a three-dimensional image if thesecond content is searched.
 10. A display method comprising steps of:searching for a second content linked to a first content; and displayinga search history of content search performed in accordance with one of afirst image and a first character, each indicating the first content,one of a second image and a second character, each indicating the secondcontent and link information linking the first content to the secondcontent.
 11. A computer program for causing a computer to perform adisplay control method, comprising steps of: searching for a secondcontent linked to a first content; and controlling display of a searchhistory of content search performed in accordance with one of a firstimage and a first character, each indicating the first content, one of asecond image and a second character, each indicating the second contentand link information linking the first content to the second content.12. A display control apparatus comprising: a search unit searching fora second content linked to a first content; and a display control unitcontrolling display of a search history of content search performed inaccordance with one of a first image and a first character, eachindicating the first content, one of a second image and a secondcharacter, each indicating the second content and link informationlinking the first content to the second content.